[Rathji]

I use 2 methods.

Study in groups. Unless you already understand everything perfectly, chances are someone else will understand something better than you. Even if they don't, explaining things to other people is one of the best ways to understand stuff yourself.

Summarize notes. Do it a week before a larger exam or a couple nights or before a small quiz. Make sure that when you are doing your studying that all the information is in a small bundle of papers so you dont waste time looking for it. Also, the act of compiling it all in your brain and then writing it down helps you understand and peice together smaller concepts into a big picture. If you can't summarize it properly, you still have time to see a prof or another student to help you understand it.