I like @Bellatrix “active learning” best. It helps if you have a study partner. Then you can engage with each other in discussing and understanding and memorizing the material. Memorizing, for me, is a last resort. I’d much rather understand the principles behind the thing. In this way, I don’t need to remember as much. I can make it up as I go along (which is what I am doing here).
One of the principles I use is the idea of feelings. If I can imagine the feelings of the characters doing whatever it is I am studying, I can probably figure out what they are doing and thinking and figure out their motives. There are principles in almost every field—from hard science to social science and in all the arts.
Another principle is to trust my intuitive responses to things. Also, teachers like you to talk and think and often will give you full credit if your thinking has any connected train of thought to it at all and if you document those thoughts without leaving out anything. Even if they totally disagree with you, they like it that you are aware of your thought process.
Anyway, I’m sure there’s lots more. Like I said, I make this up on the spot and for some reason, a lot of people buy it. Whatever. If it works, who is going to complain? If you do stuff like this, you will gradually become more confident in your studying skills, and your ability to make stuff up, and oddly, that makes it easier for you to retain stuff you read. You aren’t worrying so much about retention. You know you don’t have to rely on it.
It’s a process. One day, you, too, may be able to sound utterly confident about things you’ve never thought of before. Worse, you may actually be one hundred percent on target. When that starts happening, you first get scared and then you start to wonder if you could possibly be living in a world you thought was so hard a moment before. Then you learn that understanding is good, but it is not sufficient. Doing is another story entirely.