Is it best to say them over and over, like while reading through a list? Or does it work better to write them out until you can get to the end of the page and by then are writing them perfectly. Some of my friends take turns in study groups asking each other questions. I have one friend I can do that with, but the others are a lost cause. So, those who have finished astronomy and earth sciences, what works to retain the information in the brain for longer than a few days?