Before you take your GMAS, I want you to take some time to review the punctuation rules we've talked about in class, but that you may have forgotten about. Here are some videos that can help you. Also, on Monday and Tuesday, when you are not with me, you will be working to practice when to use these forms of punctuation.
Another thing you might want to do is take some online quizzes to help with these topics. I've gone ahead and linked to some that might be helpful for you. (Also, simply googling something like "run-on sentence quiz" will yield about a billion results.)