To be a good student requires that you pay close attention to what is being said in class. If you have perfect recall (remembering everything that has been said since the 1st grade) then that is all you may need to do assuming there is no outside class work (but almost no one has that level of recall). If you do not have total recall, then you need to take notes to jog your memory.
Paying attention and taking notes are the most important things you can do, assuming you study your notes. Accidents can happen on the road when you get distracted while driving. Well, accidents can happen with your learning when you get distracted in class. Taking notes is one of the best ways to prevent you from being distracted. Good Luck (luck is a product of hard work).