Remember, your first draft is never your last draft!
We live in a very, very busy world and sometimes it seems silly to write a story over and over again. But as an author, I can tell you that you are never finished after your first copy...you need to keep revising, fixing, and changing. I like to break it into steps. First, I read my story aloud...never silently. When you read it silently, it sounds wonderful inside your head. If you read aloud, you have a better chance of finding your mistakes. As you read aloud, listen carefully. Did you start four sentences with There was or used the words really good over and over? That's okay, now you can change them. Next, check for mistakes. After you have made your changes and fixed your mistakes get someone else to look it over. Keep in mind, you only have to change what you agree with.