For materials that I legitimately want to learn (usually finance, business, investment, programming, psychology and even some of the higher math courses), I do something similar to Puffin's writing technique. Except I usually try to make the notes reusable so I can reference them in the future. I am filling up several books with notes on various fields I want to master.

I kind of want to see how far in Physics and Math I can get, and for programming I am actively applying newer and better programming methods to whatever I want to design for fun. I feel like application of learned material is key. Beyond that, I especially agree with Darkmatters' suggestion of paraphrasing into your own words the notes you take. It is REALLY helpful and gets you thinking and putting together what you are learning with what you already know. I think that's why they say that by teaching others, the teacher learns as well.

I also love Mnemonics, but only when there are a few. If there are too many, then all that effort collapses and I forget most of them.

I gave up truly studying material that doesn't interest me (usually some English classes, most social sciences, and things that I don't see myself applying in the real world). For these, I usually use lecture notes and do a quick read and write before exams for about an hour (with some level of rote memorization), and then I...wing it. Saying this makes me cringe. I hate that I am not interested in certain subjects, but I made peace with this procrastinator method in high school years ago. And it almost ALWAYS results in a good grade which is the very validation that I, at some level dislike, as it proves to me that the lazy method can also work. x_x