Producing your first draft is a major milestone. Many authors, myself included, compare it to having a baby, especially if you ever actually HAVE had a baby. At some point in your story, you may feel as if you’re 9 1/2 months pregnant and really want to be done with it.
When you do, by all means celebrate! You deserve it! But don’t think for more than one glorious day that you’re finished. No matter how great your work seemed as you put it down on paper initially, chances are it can be improved. Probably a lot, depending on whether this is your first book or tenth or more.
If the first draft is comparable to a pregnancy, the second draft is comparable to potty training. If you’re a parent, I probably don’t need to say any more to complete the analogy.
When you get to what you think is your final draft, (probably comparable to raising teenagers) start tightening your story by trimming adverbs, adjectives, and prepositional phrases. Many adverbs go away when you select the correct verb.