Ah, I understood you to mean how to not forget studying.

For doing studies, try mindmapping, writing summaries, do self tests or assignments. This applies to any subject that is about insight, biology, chemics, physics, history, etc.

It is also (for most) better to focus hard for 20 minutes and take a 2 minute break than to cram for hours, your brain needs breaks to decompress, having a higher studying yield in the long run.

Oh, and keep your phone in another room, phones are attention killers!