Write your body language into your story

But don't overdo it and beware of repeats. The Milennium Trilogy overdoes the number of times that its characters 'bit her bottom lip and stared out the window'.

A little is effective but make sure it is only once in the book.  You would be surprised how readers pick up on repeated phrases and tire of them fast.  Even habitual nail-biters can be darn annoying.

Here's a handy chart that employment agencies use when people are going for jobs. 

It is a chart of notable body language clues to emotions and it is the sort of stuff you can research to put into your books to denote TYPE or to BUILD characters.. Or people can use these in a studied way to project an image they prefer or need at the time.

Crossed arms: Anger, defensiveness

Moving away, tilting a chair back: You are too close, space is invaded

Fidgeting, tapping foot or fingers: Nervousness, boredom

Slow, deliberate walk: Confidence

Standing with hands on hips: Readiness, aggression

Sitting with legs crossed, foot kicking: slightly Boredom

Sitting, legs apart Open: relaxed

Touching, slightly rubbing nose: Rejection, doubt, lying

Rubbing the eye: Doubt, disbelief

Hands clasped behind back: Anger, frustration, apprehension

Locked ankles: Apprehension

Head resting in hand, eyes downcast: Boredom

Rubbing hands: Anticipation

Sitting with hands clasped behind head: Smugness, superiority

Open palm: Sincerity, openness, innocence

Tapping or drumming fingers: Impatience

Patting/fondling hair: Lack of self-confidence; insecurity

Stroking chin: Trying to make a decision

Looking down: face turned away Disbelief

Biting nails: Insecurity, nervousness

Pulling or tugging at ear: Indecision

Adjusting tie: Insecurity, nervousness

Putting tips of fingers of one hand against tips of the other hand: Confidence

Clearing throat: Nervousness