(more character development do's and don'ts from my upcoming class)
Don’t… explain a character’s response to a situation—or to another character—when action would prove their response.
Especially don’t use internal dialogue to do the ALL work for you. This is cheating the reader from experiencing the hero/heroine’s reactions and coming to their own conclusion about what the hero/heroine is feeling or thinking. Internal dialogue should only tell the reader what they can’t see or know for themselves, such as secrets, memories or unexpected reactions.
Do… use body language and external dialogue to show how a character feels or thinks.
Actions speak louder than words. Character postures and actions more potently reveal if they are nervous, hurt, excited or dangerous. Since words can be false, most humans instinctively register actions in their subconscious to weigh truth.
When you pit actions against the reader's expectations, you can create especially tense situations.
For example, a woman with her husband at a party may meet a handsome, sexy, powerful man. She may speak casually to him, as if he's no more important than the bartender. But if she’s attracted to the newcomer, she’ll likely open her chest or her body, bare her neck by pushing away her hair, dilate her pupils, touch her neck or rub her ankles together. She may even laugh at his bad jokes.
Her husband may start to insult the man as a power-play to hide his insecurity. But in the end, her navel will point at the man she wants to go home with. Same for the fellows; whichever man takes the posture of the gorilla—chest out, chin raised, back straightened to the point of being arched, jaw set—is likely claiming territory.