1) Always start studying at least 2 nights in advance. That way, the information can sink in better.
2) Pay attention in class! Getting good grades doesn't just mean studying your butt off all night for a B! Make an effort in class, you'll be surprised on how much you already know when you go to quiz yourself.
3) Make preparing for a test or quiz fun! You could make little games for yourself. For example, every time you get 5 questions correct in a row, allow yourself to do something quick and fun. Such as listen to your favorite song, or daydream for a minute. That will not only drive yourself to get more questions right because there's a reward coming up, but that little free time will allow the information to sink in.