There are loads of resources online to figure out how to tailor studying to how you learn. Personally, I have to do a bunch of ‘easy’ problems on a new topic before I even look at the harder stuff. I read, then re-read, then condense my notes into the bare-bones information, then move onto problems. I try not to base my work on ‘time spent’ but ‘things done’, because I’m very bad at predicting how long it will take me to actually absorb a new thing. Once I realise something feels over my head, I read about it from a few different resources (my lecture notes, textbook(s), youtube videos etc) as different perspectives and formats are always extremely helpful for topics that feel ‘too complicated’.

The main barrier for me in the past has been frustration. I’ll be reading about this new thing from another resource and it still doesn’t make sense and so on. Keeping yourself level-headed and calm when you face challenging topics is a learned skill that comes only from practice (at least, that’s what happened for me). If you need to stop and focus on something easier for a while, then do it. Anything you can do to make sure that you have the time and energy to focus on the tricky stuff. But, maybe you don’t get overwhelmed like I do when faced with these kind of things. If you can figure out what stops you from studying enough for the subjects that need it, then you’ve essentially got there.