Damn…that’s a really good question. When I wrote my epic fantasy book I started with a map. In fact, I even wrote a little blog about it! After I had the map down, I thought of the name of some characters in hopes that doing so would invoke a story…it didn’t. Really, it wasn’t until I conjured an image in my mind of a lean, confident, commanding man in study at the top of a tall tower. He ended up being an emperor who sacrificed himself to buy his people enough time to escape a ravaging horde, and to settle on some other continent.
The point is, asking where to start your manuscript is like asking which shoe should you put on first. There’s no wrong answer. The problem, I feel, doesn’t arise from choosing where to start your novel; it arises in the simple truth that there are so many starting points to choose from. It’s like tackling an overgrown yard—you just gotta pick a spot and start working. It’s really no different with writing; you have a jumble of incomplete, budding ideas, each begging for precedence. But don’t let it overwhelm you. I think I jumped from character creation, to world building, to outlining scenes, to plot development, and everything in between before the book started to take shape. At times it seemed that the deeper I delved into the story, the more I realized how much I needed to flesh out. It was like I was taking one step forward and three steps back. But I kept working at it, fleshing out details as they arose until I was taking three steps forward and one back (you never really get away from having to take a step back, no matter how successful you become).
Eventually, I found my groove, but what I did may, or may not work for you. I outlined my book into scenes, and then made each scene into one or more chapters. When I started writing my nonfiction (still a work in progress), I started with the elevator pitch (a two sentence pitch about your book that should take no more than a few seconds to say…about enough time for an elevator to move a single floor), and then divided the pitch into several different topics. Each topic then became a chapter. Stephen King begins with his elevator pitch (e.g., a cat saves a little girl from wall-dwelling troll the size of an action figure), heads to his basement and slams out an entire novel (kind of like the author on Misery…coincidence?). I am an “outline writer”; Stephen King is a “discovery writer”.
But where do you start? Maybe try with your elevator pitch (in one sentence, what is your book about? For example, from The War of Ages Saga: A young slave girl is given the power of a god, and must rediscover her humanity if she is to free her people); maybe create a character like you would in D&D, but actually flesh out his/her background; maybe start writing one of the scenes, floating in your head and see where it takes you.