When you are excited about a story you want to just write and let words run wild. You want to let them take you wherever they can. You may think of three different ways to say the same thing and they are all so exciting that you write them all down. You may have ideas that aren't quite fully formed but still NEED to get onto the paper. That's awesome. That's writing.
That's maybe 50% of the work, if even that.
Rewriting is taking those spots where you said the same thing multiple times because it was so exciting just to be caught up in the world and cutting down all but the BEST.
It is taking those half-baked ideas, asking them what they are REALLY trying to say, what they really NEED to say, and putting them in the right order to say just that.
Rewriting is where the work is, and it is completely essential.
Some basic "rules."
If you find yourself saying how something or someone looked in an abstract rather than a concrete (ie "he looked tired" rather than "his eyes were bloodshot and watery."), rewrite it.
If you see a modifying word like "just," "very," "rather," etc, ask yourself, is it really necessary (really is another one, by the way).
If you see "was doing" anything, try and change it to "did." (ie "He was eating" becomes "He ate.")
It is all really important, and it is something you can learn to do. Following the rules of writing is teachable. Imagination and story building are not (in my opinion, some might disagree). One is a discipline. The other is a gift.
If writing were easy, or simply a matter of natural ability like having a good singing voice or athletic prowess, then no one would ever have to work at it. I read a Hemingway quote (on Pinterest, I'm not nearly academic enough to be reading Hemingway on a daily basis, so this is not me trying to be smart. I just spend too much time on Pinterest) that all writers are apprentices in a craft with no masters. I know people who can't compose a coherent text message and here we are trying to write 50k word plus monsters with no promise of restitution or recognition. Why? Because we can? Because we sort of have to? I don't know.
So get to work!
Some Useful Posts on Rewriting:
Pen, Paper, & Perseverance: Is your Manuscript Obese?
Smart Kids Explain Rewriting (for kids but it is an enjoyable video)
TypativeMamaCat-Handling Constructive Criticism
TypativeMamaCat-Editing is a Cruel Cycle
AuthorCulture-The Ten Most Overused Words in Fiction