Everyone is a bit different in terms of what methods work to retain information. Here are some that help me:
1) Writing notes out more than once really helps the information stick. I was always a note taker in class, and I continue to take notes during video lessons (or else I forget the info).
2) Flashcards work for many people, especially helpful for materia medica.
3) Study in short stints, and then take a little break (repeat).
4) Make sure to be hydrated, and fed well with enough complex carbohydrates (combined with protein and fat for blood sugar balance). The brain requires a steady stream of glucose, so this is important!
5. Explain the information or concepts to a friend. By vocalizing it, you see what you need to study more of.
6. I honestly find herbs like lion’s mane and siberian ginseng to be very helpful for memory. Diffusing and taking rosemary works well too.