One of the questions I get asked most is "How do you invent your characters?" Or, put another way, "What's your process for creating the men, women, children, and other non-humans who inhabit your books?"
My answer, truly, is that I don't know. I think of circumstances, the person comes to me, and the events of his or her life alters the perception. But, let me state again, I'm a people-watcher. I'm a people-watcher with a dash of empathy -- watching, trying to understand what's going on -- and even if ten minutes later I don't remember what I've seen, it's still in my head, jumbled around. Ending up eventually, I'm sure, on the page.
Take a look, for a moment, at the picture below. I took that just a couple weeks ago, while visiting the Forbidden City in Beijing. See that face? The expression in her eyes? The dot of blood on her tissue? Even her clothes, her jewelry. That's character. That's not an invention. That's real life.
And you want real life in your books, even if they're populated with unicorns and shape-shifters, or men who turn into wolves. You want the characters to be real -- so real they could walk right off the page (into the head of the reader).
Everyone has a different way of approaching character development and creation. Find the process that works for you. But, should you be feeling a bit stagnant, or at your wit's end, take a walk. Go to the mall, or grocery store; or better yet, any place you can sit and watch folks come and go. Look for old portraits on the internet (try Nat Love or these outlaws).
Stare into those eyes. Imagine what's going on. Build a world inside that heart.