To anyone whose illustration work includes characters, facial expressions are like this computer monitor: if it doesn't work right, then all the brilliant engineering that went into building the hard drive is wasted.
The human face ranks at the very top of the hierarchy of things the eye is immediately drawn to: if a face is visible in a given composition, the very first thing we look at is its expression. The body expresses action, but the face is a window into someone's inner life, and the expression of this inner life in a character makes all the difference between a skilled, observant artist (or writer) and a wooden one. These are two massively important reasons why we should really work on this particular skill. A facial expression that is alive can make up for some weaknesses in proportions (partially because it will keep the eye from wandering away from the face!), but not the reverse – a character with a face like a wax mask is a turn-off.
In drawing facial expressions one has to deal with the dichotomy of reality versus representation. Just like theatre actors have to support their acting with more gesticulation and theatrical speech than usual, because "normal" facial expressions can't be easily seen by the audience, so do we have to bypass "what a sad face would look like" and aim for "what facial clues would be read as sadness". In other words, an illustration needs to make up for real-life clues that are not present on paper.
In this tutorial I discuss the parts of the face that change to express emotion, then go on to show how a wide range of facial expressions is achieved. I tried to include many emotions that are complex yet often used, but by no means does this represent the full range of what a face can express. The diagram works much like a colour wheel: any two colours can be mixed, but if you mix too many of them, the result is an indefinable greyish hue. Similarly, we can feel many emotions at the same time, but the more numerous and/or contradictory they are, the more the face takes on an ambiguous mask as if they cancelled each other out. There is no recipe to successfully achieve this, just one big rule of thumb: how well you draw an emotion is related to how well you are able to stimulate that emotion in yourself, in other words to feel it as you draw and be aware of how you react to it – exactly as a convincing actor does.
The Emotion Tree used here is my own branching system and one I find convenient, but it's certainly not a scientific classification, and it's possible to arrange it differently. The labels are best understood as relative to each other rather than as absolute values, because different people will not only express emotions differently, they'll also interpret them differently depending on experience and culture. The emotion I label as "angry" may look "furious" to you, or maybe your character is so stoic that his anger would only look "upset" on my diagram. What really matters here is that "angry" is stronger than "upset" and weaker than "furious". Here’s a useful fact though: Studies indicate that the facial expressions of happiness, sadness, anger, fear, surprise, disgust, and interest are universal across cultures.
How Facial Features Show Our Feelings
Much can be done with the eyes alone. The interplay of eyelid, iris position and pupil size creates subtle but perceptible differences in expression, as the eyes are the main point of focus in a face. They dominate the whole expression, so make sure you have the eyes right before focusing on the rest. In the Emotion Tree, the eye opening and state of the pupil are described with the terms in bold, as defined below:
By alert I mean the eyes in their natural state when we are active. They don't have to be more open than relaxed eyes, but in a drawing style that's not very detailed, the eyelids should not be drawn because they give a "non-alert" clue to the viewer.
The pupil also has three sizes:
A dilated pupil does not happen with an alert or wide eye (the only exception is a state of deep terror). A contracted pupil does not happen with a relaxed or sleepy eye.
Note that light eyes (blue, grey) always look wider than dark eyes, and inversely, dark eyes always look more relaxed than light eyes. Adjustment of the three factors one way or the other is always necessary to make them look right. Because I need to show the pupil, my diagrams all have light eyes.
The eyebrows are very subtle. I find that the least change brought to the eyebrows can change the expression I’m drawing. For our purposes we can divide the eyebrow into two parts that can move semi-independently: the head and the curve. I say semi- because the one always ends up pulling the other a bit. They can both be at rest, raised or lowered, and the combination of these two contractions achieve expression as shown in this table:
Each contraction can show various degrees of intensity, which also affect the overall shape (and create furrows above the nose and on the forehead), so we end up with many very subtle variations that can’t really be shown in a chart. Use instinct and observation skills. The Emotion Tree shows a good range of examples.
The mouth area is second only to the eye area for expression. You'll find the details of lip positions (and additional expressive features such as dimples, teeth...) within the Emotion Tree, but here's a note on mouth shapes, which are created by the combination of the curve of each lip.
- Both lips curve up: grin, generic happy (open) mouth shape
- Upper lip curves down, lower curves up: extra happy – the mouth is more open than usual, perhaps to shout.
- Both lips curve down: dismay, fear (the corners are relaxed but the lower lip pushes up in anguish).
- Upper lip curves down, lower curves up, but this time the upper part is larger: jaw drop. All is slack.
- Lips look like they want to join in the middle: caused by the corners, which are lifted into a snarl: this is the angry open mouth.
The nose isn’t the most expressive feature, but it does flare under certain emotions (anger, crying, disgust, arousal) and even wrinkles at the base during extreme anger and disgust.
The Emotion Tree
This is my classification of 58 common facial expressions, most of which can be combined together if needed. From the Blank face, it branches out into five great emotions: Relaxed, Surprised, Smiling, Angry and Sad. The characteristics of each expression are detailed below.
The Relaxed Branch
Characterized by horizontality of features and lack of extremes – no facial distortion.
The blank face is the starting point for all emotions, but is discussed here to be distinguished from the relaxed face. In reality, the blank or neutral face is the relaxed face, but does not necessarily look it. People's individual features interfere; some people when totally relaxed, look like they're frowning, others look like they're smiling. So on paper, to make a face look blank, we need the following points:
- The face has no expression but is not slack.
- The eyebrows are neutral.
- The eyes are alert but can be relaxed for a blank-and-unfocused look.
- The pupil is tangent.
- The lips are closed and neutral (straight horizontal line)
To distinguish this, on paper, from the blank face, we need to emphasize the feeling of relaxation.
- Turn the mouth slightly up. The smile is almost imperceptible but makes it clear this is a rather pleasant feeling.
- The eyebrows are still neutral
- The eyes are relaxed, pupil covered and comfortably dilated.
The inner peace and serenity manifest in the absence of any tension in facial features.
- The only real difference with “relaxed” are the closed eyes, as if in trust and surrender.
- The fact the eyes are closed makes the eyebrows droop a little.
- The eyelid and area around relaxed closed eyes are smooth, with the lower eyelid curving up.
“Aahhhh...” The face that sells cleansing products and pleasant smells.
- The only real difference with “Peaceful”: the smile widens and lips part in an instinctive reaction to something that pleases the senses. Note that if the stimulus gets stronger, it results in the "Savouring" face.
“Mmmm...” The senses are pleased!
- The smile widens, the corners are compressed, dimples may appear.
- The eyes are still closed, for the same reason.
- The head tilts back as the chin is raised – moving back from worldly things to better focus on the feeling.
The heavy eyelids combined with a smile betray the fact this person is not only “relaxed”, but has every intention of being idle.
- The eyes are sleepy, pupils at least half-covered: the tonus in the eyelids is less than the normal waking state.
- Even the eyebrows are flatter than usual.
- The smile is slight – less effort!
The loss of tonus is no longer something enjoyed, but is due to loss of energy.
- The head droops forward a bit.
- The eyes are sleepy.
- The eyebrows are plaintive.
- Pockets start to show under the eyes.
No energy left, everything slumps.
- The head droops noticeably.
- The eyebrows are more plaintive, even painful.
- The eyes can barely stay open.
- The pockets are emphasized.
- The jaw is relaxed enough to drop slightly.
Nodding off. It's a different kind of tiredness, not due to overexertion, and as a result no strain shows (unless one is both tired and sleepy).
- The eyebrow is strained over the eye we're trying to force to stay open.
- The head nods forward and very likely also tilts to one side.
- The other eye and eyebrow are totally relaxed as if asleep.
- The mouth is neutral.
“Huh? What?... Where’s my coffee?” That state where we're emerging from sleep with great difficulty, a.k.a. Monday mornings.
- The eyes are unfocused and bleary.
- The eyebrows are bewildered.
- The mouth is confused.
"Dead bored" is an insightful expression: All the features are horizontal, as if seeking to be more blank than a blank face.
- The eyebrows at their flattest and low on the eyes.
- The mouth is slightly turned down (boredom is not pleasant), but not enough to look like there is an effort involved.
- The eyes are sleepy.
The Surprised Branch
This is a smaller area than the rest, because surprise is usually incorporated with other emotions, but here we're looking at pure, "unflavoured" surprise, neither positive nor negative. Its overall characteristic is opening and roundness: first of the eyes, then of the rest of the features.
The only change from the Blank face is the interest expressed in the eye region.
- The eyebrows lift; one may lift more than the other for emphasis.
- The eyes become alert and focused.
- The mouth might open slightly as if to take in more.
The typical reaction to something unexpected. The head is usually simultaneously jerked back.
- The mouth puckers; this is more a stylistic effect than a real reaction, reducing the mouth to bring all the focus on the wide eyes.
- Wide, rounded eyes (with iris nearly free) and eyebrows
- The mouth may be slightly open.
“I can’t make sense of this...”
- The eyes squint a bit as if staring at the problem, looking downwards.
- The eyebrows frown in focus.
- The lips are pursed in reflection.
- An eyebrow is optionally raised in worry (”Am I going to figure it out?”)
- Behaviorists have observed the following differences between the genders: When perplexed, men tend rub their chins with their hand, tug at the lobes of their ears, or rub their forehead/cheeks/back of the neck. Women on the other hand tend to put a finger on their lower front teeth with the mouth slightly open, or pose a finger under the chin.
This is in reaction to something not only unexpected, but that we'd never have believed possible. It tends to be accompanied by a forward tilt of the head, so that the eyes have to actually look up to whatever is impressive (or the idea of it).
- Eyes are wide, but eyebrows neither rounded nor lifted (the reverse of “curious”) – as if not all of the face really wants to believe the news yet.
- The jaw drops a bit
“Surprised” on a much more intense scale, utter disbelief, aliens landing, an animal asking you the time, things like that.
- The jaw drops: as this means it goes slack, the mouth remains narrow. Opening wide, as in fear, would require muscular effort that is not available just then.
- The eyebrows lift a lot.
- The eyes are at their widest, irises free.
- An optional round line around the eyes illustrates the idea of their popping out of their holes.
- The lips don’t curl, so teeth don’t show.
The Smiling Branch
Characterized by facial features curving up.
This is the smile known as polite, intentional, weak or “false”. It is betrayed by two signs (but not to be confused with a slight but genuine smile, such as in “peaceful”):
- The lower eyelids don’t contract, creating no crow’s-feet at the corners of the eyes.
- The lip corners stretch horizontally instead of curling up.
This is the smile often worn in photographs, because it doesn’t distort the features. In some cultures such as in South-East Asia, such a smile can signal embarrassment or even polite refusal.
A heartfelt (also known as zygomatic) smile is a reflex that cannot be faked.
- The lower eyelids contract, crinkling the eyes, often creating crow’s-feet lines.
- The corners of the mouth curve upward, which makes the whole line of the mouth move up slightly on the face.
A “Real smile” that has picked up so much intensity the lips are forced to part and reveal teeth.
- Eyes are the same or even more crinkled.
- The corners of the mouth are more evident, with lines connecting them to the wings of the nose.
- The triangular flash of teeth is a powerful happy signal.
This emotion wants to come out, so the features, though still contracted, open up.
- The eyes are wide but you can still see the contraction of the lower lid.
- The eyebrows are lifted.
- The grin is huge.
The dam has burst and the face freely pours forth joy and excitement.
- The eyebrows are round and high.
- The eyes are rounded and the irises can be free.
- The grinning mouth opens – it’s hard to keep quiet in this state.
Here taken as a neutral emotion; for negative associations see “Haughty” and “Arrogant”.
- The eyes are closed and relaxed, contemplating one’s own achievement.
- The smile is somewhat smug.
- The chin is held high, head tilted back.
When things are going our way but we try to hold the satisfaction in, out of politeness or mischief.
- Eyes closed as if to hide the self-satisfaction.
- The lower lid pushes up, crinkling the eye more.
- The broad smile is real, but the mouth is pinched at the same time, again to hush the gloating; this creates more lines.
“Oops! That’s funny.”
- The eyebrows are lifted.
- The eyes are particularly alert, the pupil a bit contracted.
- The smile curls up much but is pinched in repression, perhaps not to offend the subject of amusement.
1. Bursting into laughter: the head suddenly tilts back. All the contraction is in the lower face, the eye region is released for now.
- The eyes are shut but can be relaxed.
- The mouth is wide open, the upper lip near flat and the lower lip describing a generous parabolic curve.
- The eyebrows are high and rounded.
- The nostrils flare.
- The teeth and tongue are visible.
2. Laughter is a violent reaction: After a while, the stress (and even pain) starts to show as more parts of the face contract.
- The head and body nod back and forth.
- The eyebrows frown or become knotted.
- The eyes contract and may start tearing.
- The mouth is still wide open but there’s an effort to force it shut.
- The nose wrinkles and the nostrils flare.
Looking at a loved one, at a child or at something adorable.
- The head tilted sideways and a bit forward.
- The eyes are soft: relaxed, with the lower lid pushing up slightly, pupils covered.
- The mouth is curved in a gentle smile.
This varies with the personality, but this is an example combining some constants.
- The head is tilted forward, a submissive cue showing approachability.
- Sexual attraction dilates the pupils and tints the cheeks red.
- The eyes are heavy-lidded, "bedroom eyes".
- The lips are everted (turned outward) in a pout to signal harmlessness and availability (both genders).
- Note also that courting couples look down a lot when speaking, and that both men and women tilt their heads as a flirting cue.
“Who me? I have no idea what you’re talking about”. This is for comic effect. Someone who seriously wanted to look innocent would keep a neutral face and a level gaze.
- The eyebrows rounded and high, as if in suprise.
- The eyes stare up or away with exaggeration.
- The mouth can take on any of a whole range of expressions, from a purse to a grin.
Today’s hardship and tomorrow’s better days are reflected together in this face.
- The eyes look up as if to imagine the future or to plead for a better one.
- The eyebrows are sad: “poor me”
- The slight smile is the real signal of hope here; without it, it's just a sad face.
The Angry Branch
Characterized by contraction, particularly of the area between the eyebrows, which gets it maximum furrowing in some of these expressions.
A light frown can mean someone is starting to get annoyed, but it's not necessarily that; the frown also shows focus, doubt, trying to remember something. A very slight frown in a smiling face makes it look determined and less vacant.
Aside from the frown, the face is still blank. It is a receptive (listening/ watching/ thinking) face: “I’m gathering data before I decide how I feel.”
- The eyes are alert, receiving information.
No ambiguity here: this emotion is milder than anger, but clearly signals annoyance.
- The heads of the eyebrows move down, and may show a furrow where they end..
- A vertical furrow is created between the knotting eyebrows.
- The jaw is tensed into biting posture that pushes the lower lip forward and makes the mouth curve down.
- The eyes are alert.
Anger causes one to stare fixedly, a very basic behaviour aiming to make the other stand down without a fight.
- The eyebrows are low on the eyes and clearly knotted, creating more furrows.
- The nostrils flare, making the wing lines show proportionately to the loathing felt towards the object of anger.
- The mouth is compressed into a line with hard descending lines at the corners.
- One of the first signs of anger is an uncontrollable reddening of the ears.
- Other signs of anger are an erect body, dominant display (hands on hips or balled into fists, palm-down beating gestures.)
Emotions can’t be contained any more and the mouth opens to yell.
- The head tilts forward, like a bull ready to charge.
- The eyebrows are at their lowest, overshadowing the eyes.
- There is tension around the eyes.
- A snarl makes the upper corners of the mouth stretch up more while the lower lip is still pushed up, resulting in this mouth shape.
- There are snarl lines on the nose, adding horizontal furrows to the vertical.
- The nostrils flare even more, with clear lines from wing of nose to corner of mouth.
- The lower canine teeth may show in the corners.
Complete reversion to blind animal fury. What happens to the human face here can be observed point by point in a furious lion or wolf.
- The eyebrows are ate the same time knotted and arched, creating lines in the forehead.
- The wide open eyes with pinprick pupil look mad and blinded by rage.
- The upper nose is wrinkled by a snarl.
- Drool or spittle are likely!
- Veins become visible on temple as arterial tension rises.
- The mouth and nose area push "Fury" to an extreme, exposing more teeth and the tongue.
In response to something despised, be it physical (bad smell...) or moral (cheating...)
- The head is tilted back, looking down the nose.
- The nostrils rise, making the wing line prominent and pulling the lip into a curl on one or both sides.
- The lower lip pushes up, curving the mouth down.
- The eyes are alert but narrowed.
- The corners of the mouth are pulled sideways, making it wider.
The Lucius Malfoy expression. It’s a sneer, but void of intensity: cold disdain. The object of contempt is just too insignificant to cause an emotional reaction.
- The eyes are relaxed, pupils covered.
- The head is tilted back, looking down the nose.
- The eyebrows are slightly lifted in disdain, barely frowning.
- The mouth is just curved down.
- The eyes may roll up scornfully.
Not only believes he’s superior, but is also quite smug about it.
- The head is tilted back, looking down the nose.
- The eyebrows are lower, in a more pronounced frown
- Smug smile: a fake smile with the center pushed up by the lower lip
- One or both corners of the mouth are pushed up in a sneer, adding deviousness and superiority
A universal, reflex reaction, basically for food but also stretching to less tangible objects. All of the features in the face reject the subject of disgust by constricting (eyes, nose) or pushing out (mouth).
- The eyebrows are quite knotted.
- The eyes are narrowed or half-shut.
- The head is tilted forward, looking from under the eyebrows.
- The nose is wrinkled.
- The nostrils rise so high the tip of the nose is distorted.
- The wing lines are deeply etched and at their longest.
- The tongue, mimicking a retching action, fills much of the mouth.
- The chin wrinkles.
- The upper lip slack, the lower lip turned out and pushing up, resulting in this mouth shape.
- The face is longer due to the mouth opening.
“You expect me to believe that?”
- A blank look (sleepy eyes with straight horizontal lids, pupil half covered) confirms boredom and disbelief (see “Curious” for alert eyes).
- The single raised eyebrow is a universal sign of scepticism.
- The mouth turns down just enough to not be amused. (Turn the mouth up into a corner smile and the expression becomes cynical.)
“Just you wait, Henry Higgins just you wait...”
- The lower eyelids close more than the upper, creating a visible pouch and making the eyes curve down.
- The eyes are narrowed as if to aim!
- The frown is upset and low but no more, saving the anger for the opportune moment.
- The mouth is puckered and pinched so that it looks hardly wider than nose.
“I am not happy with this, but I can’t/won’t get confrontational about it.” Most often seen in children, but a mild pout is an involuntary reflex when disagreeing.
- Accusing eyes stare from underneath a frown.
- The lower lip pushes up, looking thicker and turning the mouth down; the chin is knotted.
- The head tilts forward with involuntary submission.
A more-or-less mock upset that is often just comic relief.
- The frown attenuated by sleepy eyes and half-covered pupils: “I am not really angry or hurt.”
- The mouth is curved down, but twisted, also signalling that it’s not to be taken too seriously.
The Sad Branch:
Characterized by the features curving down. All this branch also shows a slump of the shoulders.
“Meh.” The face is almost neutral, with just a hint that all is not well.
- One corner of the mouth pressed, as if a smile had been attempted and failed.
- The eyebrows are neutral
- The eyes are relaxed, pupil tangent.
The main difference with "Sad" is in the eyes, which, comparatively, are relaxed in resignation. This is what sadness turns into after a while, as the pain is dulled but not lifted.
- Consequently, the iris is wider and at least tangent.
- The eyebrows can droop a little or a lot.
One step beyond “Blue”, there is no energy left to even be sad. The resignation has turned to hopeless indifference.
- The eyes are downcast and sleepy, iris barely visible, pupil dilated. They can be closed, shutting the world out.
- The head is bowed or even hanging.
- The eyebrows can be almost neutral, as if it took too much energy to keep them in the “sad” position.
A pained look, the cause of the sadness is still fresh in the mind. All features droop down on the outside.
- The eyebrow heads rise and come closer together, but there's no visible tension here yet: this is pure sadness without fear or anger.
- The eyes are alert (to the fresh hurt) but the upper eyelids slant downwards and can show a fold emphasizing this. The pupils are free.
- The mouth curves down.
- “Silent tears” may roll down the cheeks.
Both hurt and in turmoil: no resignation here but a desperate desire to reverse the cause of the hurt.
- The eyebrows heads rise so much they create tension.
- Tears are very likely.
- The lips part as if the pain was too strong to be contained.
- The corners of the mouth curl down and the lower lip pushes up in an involuntary but irresistible pre-cry muscle reaction.
- The pupil is free as the eyes widen in fear (of being unable to undo the hurt)
Crushed to the point of heavy, sobbing tears; this shows the maximum facial distortion in this branch.
- The eyes are forced shut or very nearly as the eyebrow pucker pushes down and the lower eyelid pushes up.
- The tension creates horizontal creases in the forehead.
- The tears are so abundant they flow from both corners of the eyes.
- The muscle spasm of the lower lip gets worse.
- The face flushes.
- The nostrils flare.
- The chin quivers.
This expression is true of an adult in physical pain, but for a child's response to pain see “Crying”. The features contract as much as they can – contraction can provide relief by focusing the attention away from the pain.
- The eyebrows press down on the eyes, the heads curling up in pain.
- The lower lip pushes up while the corners of the mouth are strongly pulled down, revealing the clenched teeth and even the lower gum.
- The eyes are closed or narrowed.
- The nose is wrinkled.
- The upper lip is raised.
- The parenthesis-like lines around mouth are characteristic of this shape and tension.
In children, disappointment would be pure sadness, but in
adults the sadness is tinted by reproach.
- The lips are pinched (to hold back reproaches), the mouth may move sideways, as if to hide the pinching.
- The eyebrows are a varying mix of sad and frowning.
- The eyes are alert, pupils tangent.
A combination of anger and a desire to cry.
- The eyebrow heads try to frown and rise at the same time, knotting and forcing the eyebrows into nearly straight lines.
- The mouth is pouty but the tension is concentrated in the eyebrows as the brain is in overdrive seeking a solution.
When too many things assail the mind, the whole face contracts as if to keep them all inside, or maybe block out the world while figuring out how to deal with them.
- The eyebrows press down on the eyes, in full frown, but the heads curl slightly up to retain a trace of pain.
- The eye slant now follows the frown, inside corners dropping.
- The lips are pinched, pushing the mouth up.
- The nose is wrinkled as the face crunches upon itself, even the tip turns slightly up.
- The wavy mouth shows uncertainty (”Where to start? how to deal with this?”
Close to “Frustrated”, but with less anger and more fear.
- The eyebrow heads are as in “Frustrated”, but the curves rise as well, creating furrows in the forehead.
“Deer in the headlights.”
- The widened eyes with contracted pupils are the central feature, staring at the threat.
- The eyebrow heads rise.
- The mouth is nervously contracted.
- In fear the hands clutch things, making the tendons stand out.
All features open as the skin goes pale and hair stands on end.
- The eyes are very round, with pinprick pupil. This captures the very moment of breaking into terror, but note that past this first moment, the pupils dilate to see better, even though the eyes are wide open. This creates the eerie, somehow inhuman look of deepest panic.
- Nose wing lines appear.
- The eyebrows are high and knotted.
- A scream of horror curls the lower lip down, revealing the lower teeth.
This also expresses mild embarrassment, as opposed to the extreme "Embarrassed". Young children show shyness by tilting the head towards a shoulder while raising the shoulders.
- The head is tilted forward and pulled into the shoulders as if to hide like a turtle
- A blush spreads across the face, ears and neck.
- Forced grin of embarrassment: the corners are stretched sideways instead of up.
Expressed by trying not to express it, in other words to make all facial expression disappear.
- Gazing down and often away, as if eye contact would spill one's secrets. The head is likely to turn away.
- The face is expressionless, trying to attract as little attention as possible.
- The features seem to shrink.
“OMG if the ground could just swallow me now!” This emotional high is expressed in the eyes, while the rest of the face is still trying to go unnoticed.
- Round bulging eyes stare down and away; the head is certain to turn, likely to the point of turning the face completely away.
- The lower lip pushes up in dismay.
We rarely express our feelings through our face alone: the whole body is the seat of unconscious gestures. Using them will make your characters look less stiff and much more natural. The hands are particularly expressive, and hand gestures have been mentioned under the relevant expressions. Here are some common and conspicuous body postures illustrators are sure to use:
Hand on Hips:
Palms on the hips, fingers forward, elbows bowed outward:
- Classic sign of confidence
- Shows the body is ready to step into action, get to work etc
- Enlarges the upper body, making one look more powerful and threatening in a confrontation (or when grounding kids)
- Also means "Keep away from me, I’m feeling anti-social."
- Note that when the thumbs are forward, the posture is more feminine and signals uncertainty rather than aggressiveness.
- Classic defensive stance
- Disagreement, closing oneself to input, arrogance, dislike. Women don’t cross their arms around men they like.
- Self-comforting posture, used to alleviate anxiety and social stress.
- Arms and elbows pulled tightly into the body signal acute nervousness.
We unconsciously touch our bodies to comfort or release stress. Perplexity, disagreement, frustration, uncertainty manifest in the fingers touching the lips, the hand scratching the head, holding the neck, grabbing an earlobe, rubbing the cheek, massaging the other hand, etc. Self manipulations increase with stress and disapproval.
It is particularly effective to show repressed anger through these cues, as they are often a way of displacing the aggressivity.
Note that in young children, the hand behind the head can express jealousy.
It's surprising how many people don't know how to show an emotion even if they have lived it again and again. The remedy to that is to observe yourself from the inside. If you can evoke emotions in yourself by whatever means (a sad or hilarious movie, thinking of an issue that angers you, watching kitten videos, anything you can think of), watch carefully, both from the inside and in a mirror, how your face is changed by it (and anything else you may do with your body). It's better from the inside, when you get used to it, because looking in a mirror can yank you out of the feeling. Alternatively, observe yourself and/or others in real-time emotional situations. We go through many of these daily; be observant at all times.
This exercise has been a meme for a while, but it's both fun and good practice: Create an emotion sheet for a favourite character (your own original or any existing one), with a certain number of expressions to fill in. In order not to gravitate towards your comfort zone, select them by a randomizing methods (such as pointing with eyes closed) You can even go further and try blended expressions or more complex ones not studied here.