I'm sure that different writers use different methods to write their novels. For me it works like this, after I have my premise and universe (see posts below), I finally set my story. For this I begin with my end, so to speak. I like to know the big climax of my story before I get down to figuring out anything else. Once I know the scene for the climax it will help me start to define my characters. And once I know who the main parties are, and how the climax will affect them, I go to the beginning of the story and figure out how to get them started down the road toward that climax.
Once I have a beginning and an end... there is this whole... middle part to deal with, the lion share of the story. It reminds me a bit of Kevin Kline in A Fish Called Wanda, when he says, "What was the middle part again?" Now, I don't just ignore the middle, at this stage I work out a rough outline of what will transpire, a path toward that epic climax that I already have planned, but... I don't force my characters to adhere to that outline. It ends up more of a suggestion list, or something to keep me going should I wonder what should be happening next.
Now, I've got my premise, my universe and world, my climax, my beginning, and my story outline, however, before I can actually start writing I have one more important stage of planning... characters. By now I have a list of my major characters and what they will generally be doing along the way, but at this stage it is critical to develop the personality of each of these people in my story.
To do this I need to understand pretty much everything about each of my major characters. What do they look like? What is their personality? Why do they have this personality? And, in order to understand this, I need to know their history, all the way back to childhood. How and why did they develop into who they are at the time my story takes place? What are their goals in life? Who are their friends, enemies and family? What haunts them from the past, and what do they desire to achieve in the future? The more you explore them BEFORE you start writing, the easier it will be to write the story, and to make the characters seem three dimensional, and alive.
This is very important to how I write my books, simply because I like to let my characters work out a lot of that 'middle' stuff in the book, rather than force them to my original outline. With characters that are fully detailed and real I no longer have to make up stuff, all I need to do is set up a situation and then see what they do.
I can't tell you how many times I am surprised by what my characters end up doing, or saying at any given moment in the story. Even though I am writing them, it is the characters that are making the decisions, and that often leads me down a path that I never saw coming.
Now, I still use that outline to setup some of the situations, and when needed I nudge my characters down that path, but I never constrain them to the path, and will often let the story go where they take it naturally. I do keep my climax in mind, and make sure that the main story that I want to tell unfolds at the proper speed and builds to the proper planned climax, but the road to that climax is filled with little surprises and scenes that I never saw coming.
Someone who wants to be a writer recently asked me how writers of big epic series keep all of this stuff in their head, and my answer was, "Well, we don't, at least, I don't. And I suspect that most writers don't." Sure, there are clues, and foreshadowing, and other things early in the story that tie into the later story, that's what having your climax and outline do for you, but there is so much that you don't know until you write it, even with the best of planning.
If your characters are real people to you, then sometimes you just go along for the ride and see where they take you. It's one of the most rewarding parts of writing a story, and if you flesh them out to start with, and give them a real life and history, they will become as real to you as any living person... in some ways, more so, because they come from your heart and soul. Good or bad, they still come from you. Let them show you the way in your story and you will often be pleasantly surprised, but no matter what, they will add to your story if you let them. And it’s nice to have friends help, even if they are the people in your books.