Besides pointing out the obvious, I will also use this post to talk about revisions, or re-visions as I call them.
When you break up the word revision, you literally have "re-vision", which is a good way to look at what you're about to do to your book, poem, screenplay, essay, etc. You've written a first draft. Huzzah. Now it's important to imagine this draft, only better. Imagine all the things it could be, rewrite what doesn't work, and adapt your original vision to something that conveys your message more concisely than before. And repeat this process multiple times.
Last year, I had a professor that had a good point about revising. She said to look at a first draft of a piece of writing as a house with a partially collapsed roof.
When partially collapsed roofs are rebuilt, the WHOLE ROOF is rebuilt. Otherwise, there's no way of knowing if the undamaged part of the roof is structurally sound.
So, basically, when you rewrite anything, it's a good idea to rewrite THE WHOLE THING. This idea works better for poems and short stories than for novels, of course. For novels, it's important to be dedicated to every. Single. Word.
Does any of this make sense? I hope so!