From an io9 article about how to tell if your novel's first draft is unsalvagable, some excellent ideas for revising your manuscript:
7) Put the thing aside for a few weeks, and then list the most powerful moments, from memory. Not the things that are great about your idea, or about your characters in theory. The moments that actually stick in your mind as moments. You wrote the thing, so if a moment sticks in your head as being especially emotional or intense, that's probably a sign that it's closest to the story you were setting out to tell. Once you've got that list, see if there's a story uniting those moments.
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9) List all of the events in your book backwards, with "because" in between them. This is also a great revision technique. "The hero won BECAUSE she had the golden apple BECAUSE she spared a witch who gave it to her BECAUSE the hero felt sorry for the evil witch BECAUSE she herself had done some bad things BECAUSE she was misled into thinking a hero needs to be ruthless BECAUSE she was young and determined to prove herself." And so on. Do those "becauses" actually make any sense, when you run it like that? Do you care about that chain of cause and effect, as a basic skeleton? If any of those BECAUSE statements are like "because I, as the author, said so," can you fix that without the whole thing collapsing?
Read the entire article here.