Sometimes, writing a novel is like suffering through a long illness. You are weak, exhausted and see no end to your misery, but you have no choice but to stagger along, day after day into the future.
Sometimes I can tell when I've written well or written poorly. Most of the time, however, I have no way to judge. It's all just writing and though I can get excited about new ideas I have while drafting, I feel mostly neutral about the actual prose during the writing itself. I can see that something needs to be changed, and I can see how, but I don't think of it in terms of "good" or "bad" so much as "works" or "doesn't work." Those times when I do think the prose is brilliant or is crap? I've discovered that later, when I'm revising or just re-reading, I can no longer tell which bits I thought were brilliant or crap when I was in the middle of writing it. So how I feel about the work while it's in process has nothing, it seems, to do with the quality of the writing. Which is just weird, you know?
Sometimes I go out for pints with other writers. Thursday night I met up with Layne Maheu (author of Song of the Crow) and over Manny's Ale and a plate of nachos we talked about his latest novel A Man of the World (which sounds brilliant and cool) and my novel The Stars Are Fire (which, after two pints, sounded brilliant and cool to me) and the future of publishing and all sorts of things. Layne was treats, so I should've had a third pint, but today is a school day so it's probably for the best that I didn't.