This is most of the reason why you need to make sure you study. With multiple choice tests, you can guess if you know a little about it, but it's significantly harder to do so with an essay.
- If you don't study for the multiple choice because you're confident, then keep studying for the essays.
- GRAMMAR. At the end of the year, the real AP exam won't grade you based on your grammar, but your essay will look gross and dumb if you don't use good grammar. Just capitalize what you need to and learn how to spell buearauaruearcracy.
- Write an outline before you do it. It takes two minutes and it is very helpful to make sure all your best thoughts are on paper before you can forget them.