Does a character's body language agree or disagree with what he's saying?
As a Speech Communication/Broadcast major and an actor, I'm always paying attention to how people's posture, gestures, eye movements, and facial expressions portray what they're REALLY thinking at any given moment. Sometimes their body language goes along with what they're saying. For example, a character yawns and the reader understands that he is bored or tired. On the flip side, certain movements can contradict what a character is saying. Some signs of dishonesty include: averting one's gaze, touching one's face, biting one's lower lip, blushing, fidgeting, twitching, scuffling feet, twirling one's hair, scratching, blinking (either more or less than normal), etc. As a reader, I think it's fun to try and figure out, based on what the author gives me, whether or not a character is being honest.
What movements are believable and interesting?
If a character doesn't care, she might shrug or turn her back on someone else. If a character is excited, he might actually jump a little and his voice might get louder. You can also think of movements that aren't quite as common (or cliche). Perhaps the character is in a windstorm and the entire time her boyfriend is breaking up with her, she's preoccupied with the futile task of keeping her hair looking nice. (Hmm, I kinda like that scene. Lots of intrigue. Might have to use it someday! LOL) Or think of other ways to describe some of the more common body language. Maybe a smile can be described as a wry grin? A sexy smirk? A wolfish sneer?
When deciding what body language to use for a character, there are many things to consider so it comes across as believable. Here are a few things to get you thinking along these lines:
1. Gender. If your 40 year -old male character flutters his eyelashes, he will come across as feminine. How characters sit, stand, and walk can also suggest that they're masculine or feminine. Be careful not to go over the top, though. For example, if your male character is always grunting, spitting, and grabbing his crotch, you need to ask yourself if guys REALLY do that stuff, at least so often.
2. Age. Younger people typically express themselves more enthusiastically and with less inhibition. For example, a three year-old wouldn't think twice about jumping up and down and shouting, "I gotta pee!" for the whole restaurant to hear, whereas an adult would probably (hopefully) excuse him- or herself discreetly.
3. Attire. A woman in stilettos will trudge through the woods with more difficulty than one in hiking boots. Conversely, a woman who's used to wearing stilettos will be more graceful in them at the ball than a girl who's only ever worn hiking boots.
Of course, this is just a short list, but basically you'll need to know your characters well to keep their body language believable.
How can body language help a writer "Show, Don't Tell"?
Adding body language is a great way to obey the "Show, Don't Tell" maxim.
a) "Please don't go," Bertha says sadly. (Telling)
b) Bertha wipes the tears off her face. "Please don't go." (Showing)
a) Casey was infuriated. (Telling)
b) Casey clenched his hands into fists and his face turned crimson. (Showing)
a) Penelope wasn't happy to see fried chicken on her dinner plate. (Telling)
b) Penelope took one look at the fried chicken on her plate and hurled it across the kitchen. (Showing)
In the above examples, the same (or at least very similar) information is being shared, yet the second examples (b) are more interesting and offer new insight into the character.
Does your character have a signature move?
In addition to weaving body language into your writing, you might want to invent a signature movement for your character.
I remember when one of my friends told me he'd seen me standing in the parking lot from his dorm room some fifteen stories high. My boyfriend and I had just been in a wreck and the emergency personnel was checking out my boyfriend to make sure he was okay. My friend could tell it was me way down there because of the way I held my right arm straight down and grasped my right forearm with my left hand. It's what I always did whenever I was nervous about something, he'd said. I'd never noticed it before then, but he was right. It's one of my signature poses, and if a writer were to write a story about me, he or she'd want to describe the position of my arms when my character is nervous.
Maybe your character, a 16 year-old female cheerleader, is always smacking her gum. Maybe your newly turned vampire is constantly touching his fangs. Perhaps your Victorian-era duchess is prone to giggling when she's in the presence of her crush. Maybe your 800 year-old alien blinks his single eye verrrrrry slowly when he's trying to comprehend English, or your grandmother character tends to dab her nose with her deceased husband's handkerchief when she's thinking of him (her late husband, not the alien).
Giving your characters signature movements is a great way to help your readers get to know them.
What are some easy and effective ways to fine-tune your character's body language?
Sure, there are many books you can read to learn more about kinesics, the study of body language. But even if you just observe people in their natural settings, you'll see what kind of movements they do and under what circumstances. Then you can transfer those gestures and movements into your writing.
You can also pay attention to a talented actor in a movie or on a TV show. Some movie characters that are excellent examples of how body language can help develop a character are: Cap'n Jack Sparrow in Pirates of the Caribbean (his walk), Bridget in Bridget Jones' Diary (her fidgeting), Kevin McCallister in Home Alone (his scream-face), James Bond in various Bond movies (his posture and poise), and Shrek in Shrek (his charmingly bashful smile).
A final note
Now that I've hopefully got you thinking of ways you can weave body language into your writing, make sure you use it sparingly so it isn't too overbearing. A good way to check is to read your scene out loud or have someone else read it for you. Remember, integrating physical movements into your writing is meant to add to what's being said or thought, not take attention away from what's being said or thought. Writing is something you'll get better at the more you practice, and using body language is a great method to get your readers into your story.