K is for Kinesics

When you're writing, every pen stroke/keystroke/pencil scribble should exist to support the characters and/or the plot. Every stroke has meaning, down to the painstakingly selected word so imbued with context and flavor that you could not possibly avoid using it to describe your MC's eye color.

Which is why you really have to be a student of kinesics for your active prose to come alive.

Oxforddictionaries.com defines kenesics as:

• "the study of the way in which certain body movements and gestures serve as a form of nonverbal communication."

As with any and all literary concepts, the key here is balance. The art of kenesics is to find a way to convey meaning with a movement. But you can't just show us your characters' movements. You also have to give us meaningful context for the movements. Here's an example from (who else?) J.K. Rowling in Harry Potter and the Deathly Hallows:

   "I'm going to wash," Harry told Bill, looking down at his hands still covered in mud and Dobby's blood. "Then I'll need to see them, straightaway."
   He walked into the little kitchen, to the basin beneath a window overlooking the sea. Dawn was breaking over the horizon, shell pink and faintly gold, as he washed, again following the train of thought that had come to him in the dark garden...
   Dobby would never be able to tell them who had sent him to the cellar, but Harry knew what he had seen. A piercing blue eye had looked out of the mirror fragment, and then help had come. Help will always be given at Hogwarts to those who ask for it.
   Harry dried his hands, impervious to the beauty of the scene outside the window and the murmuring of the others in the sitting room. He looked out over the ocean and felt closer, this dawn, than ever before, closer to the heart of it all.
   And still his scar prickled and he knew that Voldemort was getting there too. Harry understood and yet did not understand. His instinct was telling him one thing, his brain quite another. The Dumbledore in Harry's head smiled, surveying Harry over the tips of his fingers, pressed together as if in prayer.

The actions in this scene are relatively few, but they are powerful in their simplicity. Harry washing his hands after just burying his loyal friend... this is a symbolic act of sorrow as well as resolve. By the time Harry clears the dirt away he has a better picture of what he needs to do next in his quest to defeat Voldemort. There is no need for excess here... no mention of turning on or turning off the faucet, or rubbing his hands together, or wiping his face. Those actions would convey a different emotion than Rowling wants for Harry here. The quiet, contemplative act leaves you with a sense of Harry's resolve.

Here's another moment from earlier in the book, between Ron and Harry:

   The sword clanged as Ron dropped it. He had sunk to his knees, his head in his arms. He was shaking, but not, Harry realized, from the cold. Harry crammed the broken locket into his pocket, knelt down beside Ron, and placed a hand cautiously on his shoulder. He took it as a good sign that Ron did not throw it off.
   "After you left," he said in a low voice, grateful for the fact that Ron's face was hidden, "she cried for a week. Probably longer, only she didn't want me to see. There were loads of nights when we never even spoke to each other. With you gone..."
   He could not finish; it was only now that Ron was here again that Harry fully realized how much his absence had cost them.
   "She's like my sister," he went on. "I love her like a sister and I reckon she feels the same way about me. It's always been like that. I thought you knew."
   Ron did not respond, but turned his face away from Harry and wiped his nose noisily on his sleeve. Harry got to his feet again and walked to where Ron's enormous rucksack lay yards away, discarded as Ron had run toward the pool to save Harry from drowning. He hoisted it onto his own back and walked back to Ron, who clambered to his feet as Harry approached, eyes bloodshot but otherwise composed.

Kinesics is a practice closely related to beats in dialogue, in that they both contain character action. The point is to understand which actions will be the most effective in gathering up the emotional context of the scene and delivering it to your readers.