This is also from Writers Ask, Issue 40:
Elizabeth Cox explains how she gets to know her characters on and off the page: “Sometimes I eavesdrop on conversations in public places, and I am struck by a phrase or a sentence that I know a certain character…”
Liz says: Has anyone else gotten in trouble for this? Dirty looks. What are you staring at? That sort of thing. I’ve gotten more stealthy with time, I haven’t gotten any dirty looks in a long while, but I do still eavesdrop and people watch.