Read the professor's comments. Re-do the questions you got wrong to see if you can understand why the correct answer was correct. Papers Start early, preferably the day you get the assignment. Of course you won't be writing yet, but at least start thinking about a topic and possible resources. You can also start searching the Internet for information or schedule a research session with a librarian.
Librarians are a wonderful resource when it comes to looking for articles, books, etc.
So utilize them - that's why they're there. Make sure your paper is completed at least two to three days before it is due. This gives you a chance to put it down and get some perspective. Come back to your paper a day or so before it is due and re-read it. Chances are you will find sentences you want to re-write, paragraphs you'd like to make stronger, or maybe just some grammatical errors you need to correct.