For your novel: 1. Make a list of your cast. Give each character a one or two line description. 2. Step back and make sure the descriptions are sufficiently different from each other. 3. Give each character one quirk. Make them irritating to at least two other characters. 4. Write a few "practice scenes" pairing two of the characters at random. These are great warm up exercises for your writing, and may generate actual plot ideas and twists.
