When I was learning how to write credible characters, I took a short course in characterization from another writer. Her approach was simply to have us answer a list of questions about each character. The beginning of the list dealt with physical attributes (age, height, weight, hair color, etc.) then became more detailed. Later questions dealt with ethnic background, accent (South Philly Italian did not appear on her list of examples but it sure came to my mind.)and what kind of food the character liked. By the end of this list, you were answering things like what would your character do if he/she won the lottery, or how would your character react to losing a child to cancer.
Since that time, I've seen this approach, with minor variations, all over the web. I guess for some of us, it must work.
But it didn't for me. In off the cuff examples like that, I wanted to make my character--well heroic. The brave mother dealing with her child's disease for example (all in capital letters of course, as is fitting for an archtype.) Or I wanted the character to give away everything she had to the poor and needy.
That isn't a realistic character--at least not in the real world. In the world we really live in, as the Mom deals with the child getting chemo and crying because he doesn't want to, the Mom snaps and tells the child he HAS to have it because it's good for him. Then she goes off somewhere and cries because, she believes that good moms don't snap at their poor, sick children.
That's real. I don't know very many saints.
So the list part didn't work for me. I did take away one good thing from the exercise. There is a file on my computer labeled cast, where I list each character's full name and physical characteristics. This comes in handy for those times when I'm having a character gaze into a significant other's eyes and can't remember if I actually know what color they are. I have a separate copy of this file in each book's master file.
As for what my characters would do in a given situation--they tend to surprise me. I don't always know beforehand. In a way, I'm getting to know them along with the reader. But I don't know any other way to do it.
Christine Duncan is the author of the Kaye Berreano mystery series. Safe House, the second book of the series is available now from Trebleheart books.