Any tips on doing research and keeping it organized?

Until recently, I’ve never had to do a lot of research. In computer science, I’d read a lot and put stuff in my head, but it wasn’t research on a specific question. Now, in law school, I have to do a lot more and I’m having some trouble keeping organized. I find that I end up going back and re-reading cases/other stuff very often.

Any tips on keeping organized?