In the way that one event often seems connected to another, I recently heard Jim Butcher (pictured) speak about his craft when I went to Dysprosium 2015. Wandering around the web I since found a post of his from 2005 on the topic of character creation. Jim is an interesting person to hear speak, if you get the chance, and is a New York Times best-selling author of urban fantasy (and in some small way influenced my writing of the Jon Seyton stories).
His post is here on LiveJournal and well worth a read. Let me know what you think and how much it rings true for your own characters.