Look around at the media center and online and find a sample essay of this kind. You can use it as a guide as you compose your piece. Having a good model can save you a lot of trouble.
I once read that a writer is only as good as the amount that he or she reads. You need to get your hands on several term papers, and then see what works that you would like to use. You will be able to see how the thesis statement was written, how intext citations look, and how the paper is structured.
Make sure that you still use a formal and standard writing style and structure- you paper will still be double spaced and composed in a size 12 very plain font. That font might be Arial. You will also still have one-inch margins all around the piece. Additionally, you will write in third person and avoid using first or second person. It will be formal without any slang in it. You will have intext citations and you will have either a bibliography page or a works cited page.
if you have a friend who is a good writer, ask him or her to look at your work. It is always nice when you can have a fresh set of experienced eyes look at your compositions. Maybe you can return the favor to your fiend one day. .
If your school has a writing lab, make sure you use it- writing labs do not cost the student anything. You can go in and use the computers and printer on your camps. The best part is that there will be an attendant who can help you with you work. Additionally, many schools provide an archive of papers for you to model after and many provide after school hours that will suit your schedule.
When you are finished, you will want to polish your piece. Several times you will want to proof it. Then go somewhere quiet when you have a lot of time, and slowly begin to make the necessary edits. Do not make any new mistakes as you do this. Once you think you are finished, put the paper away for a few days. Then take it out one more time and then check it before you submit it.