My good friend, Bob Resta, recently commented to me as follows:
Bob was right. For nonfiction, I set up an outline, write a draft, revise it once, maybe twice, and there it is. Easy. For fiction, my characters pay no attention to any outline I give them, and I end up doing just what Bob said, chiseling away at that rock, first on a macro scale, then in finer and finer detail.
At first thought, that seems opposite to what I'd expect. Shouldn't a relaxed voice be well-suited to telling a story, and a more thoughtful voice be more appropriate to organizing a bunch of facts, theories, or legends for a reader? Not necessarily. In nonfiction, no one's there to mess around with your outline. Even a nonfictional person in the narrative is going to have trouble rebelling against a fact-based outline.