All good writers revise their prose before submitting it.
Revise your paper at least twice before submitting it to your instructor. If you are using a word processor, you may find it useful to print out each draft and mark your revisions on the paper draft. Then enter them on your electronic copy. Before revising your first draft, put it aside for at least a day. Then come back and attack it, looking for every possible problem that you can find and solve by revision.