Today we spent the day reviewing for tests, and I realized that my advice for studying is probably different than that of their other teachers.
One, I realize I do not like answer keys for review problems. Your friends should be enough to check to see if you're doing the problem correctly. Also, ask me if you're not confident. And, if you have an answer key, you ruin the precious resource of questions. There are only so many questions I can ask, and if you just read the answer, you ruin the chance for your mind to make its own connections.
Two, reading isn't studying. Only answering questions is studying. Challenging yourself is studying. Checking whether you did it right is studying.