Just write. I threw away three novels before I'd honed my craft enough to publish a finished book. Don't be afraid to edit the living daylights out of your manuscript, but get it finished before the editor steps in. As Ernest Hemingway said, "The first draft of anything is shit."
An editor I work with once threw away 90,000 words of a novel he was working on. 90,000 words! So just write, and don't worry about the finished work until you've got a first draft done.