I love creating characters and writing dialogue, it’s plotting a novel or screenplay that I find the biggest challenge. Therefore I’m always interested to find out how others approach it. It’s not that I think there’s a formula that will work for everybody, but the more we know about how others do it, the more easily we can construct or discover our own.
Here’s what novelist Terry Odell told the Writer’s Knowledge Base Newsletter about her way of working:“…being "trained" in the romance genre, I follow the GMC (Goal, Motivation, Conflict) format. My characters want something. I refuse to give it to them. And I try to find characters whose basic goals don't match at the beginning of the book…
"As a matter of fact, I think that's my basic tension-creating premise. Start with characters who have very simple goals, and then see what it takes to push them farther than they'd ever dream they could go. I prefer not to give them the skill sets they need to solve the problem. That would be too easy. They have to dig deep and discover what they really can do. And you need to have tension on every page, in every paragraph. Your character has to want something (or NOT want something).”
On her blog, Odell wrote several posts about how she did this in one of her novels. You can find that here: http://terryodell.blogspot.com/2011/06/its-about-conflict-and-tension.html
(You will find plenty of helpful and practical guidance to writing your novel in my book, "Your Writing Coach," published by Nichoas Brealey and available from Amazon or your other favorite bookseller.)