Today's wisdom comes from my experience with editing manuscripts, whether they be my drawer full of half-finished novels, or those few short stories I write every once in a while.
When in doubt, cut it out (or, more positively, go with your gut feeling).
Now, this isn't to say hold the delete button over paragraphs that you aren't sure about. When you're going over your rough draft, and something doesn't
feel right, take that word/sentence/paragraph/scene/chapter and move it to a blank document. Delete it from your original draft, and analyze the story again without it. Nine times out of ten, the story is better off. On the other hand, sometimes, what you've taken out needs to be woven into the story elsewhere, because it is an important part of your story, just in the wrong place at the wrong time. You'll usually have a gut feeling about these parts of your story, but you'll be scared to change anything, to cut anything, because you just worked so darn hard on it.