One great way to really learn a topic is to teach it!
Challenge yourself to plan a lesson on the topic you are revising.
What key information would you need to give your students?
Which key words do you need to define and explain?
What activity could you set them to deepen their understanding of the topic?
What questions will you ask to check that they understand?
This is a great way to check your own understanding. Once you have planned your lesson, you could use it in a study group if you are revising with others in your class, or you could teach it to somebody else who would just like to learn something new!
You could arrange with classmates to plan different lessons and teach them to each other - this helps everybody!
Even if you are studying alone and not going to actually teach your lesson to anyone, the process of planning it will help you to learn and remember.