Hi devil, great question!
The best method for studying is highly dependent on you and on your subject! I.e., what works best for you (how does your brain remember stuff the easiest?) and what kinds of things are you studying?
There are several techniques you can try out and you can see what works best
- Re-reading your material (silently or out loud)
- Writing down a synopsis of your material
- Listening to/watching people explaining it
What does your material look like? Is it something formal/science-like that you have to understand? Or is it a big list of things you have to remember, like anatomy or translations?
If you want to understand things, don't just read the material, question yourself on how it work and why it works the way it does.
If you want to remember stuff, then keep using one of the above methods periodically (every few days). Every time you read/watch/write something, you put it "better" into your brain for the long term.
What worked/works for me: I used to just read the book/course material and make a big, very high-level synopsis of everything (this would sometimes just be a list of the titles and sub-titles of the book). Writing stuff out also worked very good for me. If you haven't tried that, I highly recommend you do it at least once to see how well it sticks. For me, if I've written something down, it's very well engraved into my mind.