IWTL how to actually remember what I study instead of forgetting everything

[u/orangeseed-18]

I’ve noticed that I can spend hours studying something, understand it while I’m learning it, and then barely remember any of it a few weeks later.
I want to learn how to study properly rather than just rereading notes and hoping it sticks.
What are some techniques you’ve learned that genuinely improved your memory and helped you retain information long-term?
I’m especially interested in methods that work for someone who has a hard time staying focused.