What have lions, birds and apes in common? Beside of being creatures they are able to learn. They have to learn otherwise they won’t survive.
For students it’s often an exhausting task. “Studying is hard, let’s go shopping“. If you just read your text books over and over then it is hard. You should acquire some knowledge about learning.
The key is summary. You have to understand your topic to shorten it to its essence. In addition you should have at least once read through your notices and books.
There are various approaches for displaying your shortened stuff. One famous approach is mind maps. Sometimes I find it very useful. Other times I prefer simple drawings or tables. I think everyone should choose its own ways depending on the specific information.
Now the information that you need to learn is shortened. You can begin to “learn” it. I prefer explaining it to someone. Otherwise I repeat it as long as I know it and try to apply it.