Ebbinghaus repitition curve. Integrate it within your notes, so when taking notes, repeat topics or sentences in this pattern 1 2, 1 2, 1 2 3, 2 3 4, 3 4 5, 1 3 5. Notice that you've covered 1 about 5 times now. Not only that, but you had to remember it after a space of not remembering it. Great for classes like psycholgoy, biology and anatomy where memorizing is key. Not so much for principle based subjects like math and chemistry. For those, you can use ebbinghaus repitition, but for the concepts.