Janet Reid said it eons ago, and I balked, but after some consideration (and the realization that I have indeed written one novel before, and tucked it safely into the past), I suppose I will have to agree with the sentiment Jonathan Evison explains so well on Three Guys One Book:
"My advice to the overwhelming majority first times novelists: first, finish the fucker, even if you sense it's not working on any number of levels-- you've got to get into the habit of seeing things through, or you run the risk of being a serial starter, or worse one of those people that has “a novel in them” who spends more time talking about it, than laying bricks. Second, bury the fucker when it's finished, forget it ever existed, and start another novel. Chances are you'll be burying that one, too."
And he also said:
"One of the problems I have with all these beautiful sentence writers that are coming out of writing programs is that the glare of their shiny sentences sometimes seems to blind them to the mechanics of story. When I read Jack London, I forget he's there. ... If I ever teach another writing class, it might be called: how to be invisible."
This point from Dennis Haritou is pretty good too:
"Beethoven revised the coda of his 5th Symphony several hundred times. That part of the work takes about a minute to play."
Oh, just go read the whole thing.