I'm putting together a framework for what I want to write, not that I'll stick to it, but I find I can't begin without an idea, a glimmer, of what's going on. I know one mystery writer (and I'm sure there are others), Valerie Wolzien, who writes the whole thing, knowing her killer will reveal him/herself by the end. He/she always does, and Valerie then goes back through the manuscript making sure clues are planted. More often than not, they're already, mysteriously, there, she says. (I think that's what she says. I'm paraphrasing what I heard in a panel at Malice Domestic a few years ago. Anyway, it's close.)
Not me, though. I have to know who my killer is. Although I had a second one crop up once. A nice complication!
No matter what you're writing, if not mysteries, you're still either a person who plots beforehand, or a seat-of-the-pants writer. None of us can figure out how the other half does it! I have written into the mist and come out okay, but it's too scary for me!
And, no matter if you're a plotter or a pantser, your story still has to have the structure a reader expects. Many resources can define it for you: SAVE THE CAT by Blake Snyder, a book about screen writing that has much in it for the novelist; THE WRITER'S JOURNEY by Christopher Vogler, a book that delves into classical forms, adapted for writers from THE HERO'S JOURNEY by Joseph Campbell; HOW TO PLOT YOUR NOVEL by Allison & Busby Writer's Guides (which I've had recommended to me but don't have--Christmas hint here!); and, lastly, a terrific book I'm about half way through, WRITING TO SELL by Scott Meredith.
Alexandra Sokoloff has been blogging on plot, especially geared for NaNoWriMo, too! Check out her excellent posts at http://thedarksalon.blogspot.com/. She uses the Three Act structure used by many.
Or you can use the tried and true plotting method. Put your heroine up a tree; throw things at her; get her out of the tree. You are, of course, free to use a hero instead. Happy writing, all who are doing NaNo!