Marilynne Robinson, in her latest collection of essays, When I Was a Child I Read Books, explores how to create a character:
For me, at least, writing consists very largely of exploring intuition. A character is really the sense of a character, embodied, attired, and given voice as he or she seems to require. Where does this creature come from? From watching, I suppose. From reading emotional significance in gestures and inflections, as we do all the time. These moments of intuitive recognition float free from their particular occasions and recombine themselves into nonexistent people the writer and, if all goes well, the reader feel they know. There is a great difference, in fiction and in life, between knowing someone and knowing about someone. When a writer knows about his character he is writing for plot. When he knows his character he is writing to explore, to feel reality on a set of nerves somehow not quite his own.