active recall methods - using things like flash cards, mind maps, diagrams and etc is actually scientifically proven to help you remember the information, if revised from properly.

diagrams and mind maps just make things look more organised and easier to read for you and flash cards prevent you from having to carry all of your books. you could just write all the needed information onto the cards and easily read through them.

if you can't find or afford the flash cards you can just use post-it notes or normal sticky notes. you can either write the small information on those notes and stick them in whatever you're revising from.

or, you could write formulae and definitions on them and stick them around the house. in the bathroom, kitchen, bedroom - anywhere that you go everyday. my french teacher actually suggested for us to do this and it does help you grasp the information in slowly but effectively.