The experts say that in developing good characters you can often make use of character “tags” – those particular habits, mannerisms, and gestures inherent to a personality. You can’t overdue it, but sometimes your readers will know who’s involved in a scene by a character tag, like:
Tapping a pen on a table
Pulling at one’s ear
Clearing your throat (my wife claims that when I talking on the phone to an attractive woman, I clear my throat a lot. She’s wrong.)
A shuffle walk
The sound of a cane
Chewing gum like it was a cow’s cud
A harsh, annoying laugh
An unusual odor, e.g. coco butter
Constant eye blinking.
I’d really like contributions to this list. Tags are helpful.