The internet is full of great questionnaires for characters. I love taking a break from the grind of writing a book to play with one of these. I can even put on my journalist hat and imagine interviewing the character--real or imagined--to see what new information I can dig up.
This week, pick one of your major or minor cast and spend time getting to know them in a new way. People move stories, illustrate theories and ideas, and rumble in the background of all great literature, no matter the genre. It's up to you, the writer, to get to know them.