There are good ways to study and not so good.
You need to experiment to see what works best for you.
The internet is full of helpful ways to study.

Personally, studying on my own, I would have to interested to know what I am to study. If I am not interested, then it becomes a real drag.
Often, I search for a reason why I should be interested in something. Once I find it, my motivation changes.
What I study is no longer censored with "this is boring", "what's this all about". etc.
Because I am interested I seek reasons to 'understand' it.

Yes, some things do take repetitive rereading to get it into memory bank.
For instance, I had to remember all the parts of the cardio-vascular system. I would imagine the different areas, such as the heart, and then try and remember all of its parts. If I got it wrong, I would re-read it, close my eyes and repeat the parts, and check. I do this until I got it right, then I would do it another 3 times in a row. Then next day, I would do the same (3 correct times in a row), then again a few days later, and once again one week later. Then I got it in my head.

Studying with friends. I found a great way is to get the person to read what they need to know, then without looking in the book (you can if only really necessary) to teach the rest of the group what was just read in their own words. This forces the person to think about it and to explain (which takes understanding of the subject to do so). We all take turns in doing this. Each person gets to hear how others explain it too. Once everybody can explain it, we all know exactly what we just learnt.