Patricia Wrede

You find out about them based on what other people say about them (“He’s a jerk!” Chris told her), based on how other people react to them (She scowled and stiffened as he came up), based on what you see them do (On his way out the door, he casually kicked the dog), based on what they say and how they say it (“Move,” he snarled and shoved past her), and based on what you know (or think you know) about their past and their motives (“Don’t mind him,” Greg said. “He just found out that his daughter is in the hospital with rabies”).

Choreographing an action scene can be done in a bunch of ways. You can get a bunch of friends together and actually role-play the whole thing (which I find a bit extreme, but which I know has been done to very good effect by a number of writers). Or you can act out the whole scene yourself, playing all the parts in turn

You can get some action figures and play out the movement of the scene.