I found writing things down helped me a lot. Simply reading out of a textook does no good to me, so I wirte down the important notes.

The shitty thing about school is you don't really know exactly which parts would be most important, but that's where paying attention in class comes into play. When the teacher goes through the textbook in class, highlight the points they are making. Thy usually don't go over single part in the book, so that's why you have to pay attention.

Missing class is no good either. That's an entire class missed, so you could end up missing a bi part of it.

So when you go to study, really pay attention to your highlighted work that was talked about in class. Study it, then write it down, then read it again.

That's how I learn anyways, is by repeating and reading the same thing more than once. Some people can learn and remeber stuff in one read. Not me. I need to read it, write it down, and visualize it.

Good luck.