Don't copy work from the web and claim it as your own. Don't steal, word for word, passages of text from books used as resources and references. Make sure that, if you hire someone else to write your paper, that they are going to write it from scratch. If you are buying a premade, public essay, don't hand it in. Use it as a reference and blueprint to write your own.
What if you want to buy a paper to hand in for your assignment? Simple! If you are going to purchase a paper to hand in, make sure that it is completely written from scratch.