Touching up

One problem I have always had with my papers is touching things up and revising them, I cannot figure out what is bad in an essay or paper because how I wrote it is how I think it's best. Through a rough draft I already fix mistakes that are written and make my story as best as it can be before revisions. So when in English class we were told to make revisions I freaked out a little, I didn't know what to do, so I did the best I can and I feel as though I could've done better.