For me, it's different for each subject:
Math- Lots and lots of questions. I'm never sure I know anything until I put it into practice.
LOTE- Engage in it as much as possible- I watch French movies, speak in it as much as possible ect. In all honesty, a lot of the time, I'm in a confusion over how to study for LOTE, it's harder than everything else for me.
Humanities- I try to avoid ROTE learning to a minimum, I reckon you're much better off understanding concept thoroughly on your own terms instead of memorizing answers straight from the text book. A lot of the time, text book definitions are too vague and ambiguous for my liking. Initially, I just try to fall in love with my humanities subjects because they are my absolute jam- from there I find the energy to read, read, read from a wide range of resources.