Here’s a mini-article by writer-editor Lon Prater. Excerpt:
For me, the biggest ways to bring depth to characters are contrast, contradiction, and conflict. They are exponentially more powerful methods than just coming up with a collection of likes/dislikes/habits/tics and having people talk about your character.
I agree fully. In the comments, I made the point that building empathy for the character is also important, and that it’s possible to have a well-rounded character for whom the reader feels nothing.
Lon’s article is short, sweet, and to the point. Check it out.
D.