I think it's best to do some work everyday - not very much though since it's only December. I'm in year 13 doing 4 subjects (biology, chemistry, maths and physics) and I tend to alternate between biology and maths one day and physics + chemistry the next day (so bio and maths on a Monday, chem + physics on tuesday then back to bio and maths and so on). So I do about 1 hour 30 minutes up to two hours of work everyday. You might want to use these last two weeks of school to see if you like that. Plan out your whole week every Sunday and stick it onto your wall or keep it open on your laptop. You can always plan ahead too. This way you're not doing hardcore revision but you're also not just sitting around worrying that you're not working. If you have mocks after christmas, then use your holidays to revise (taking a break during christmas if you celebrate). If not, just continue with up to two hours of work per day, and then start hardcore revision around march (I think the easter holidays are really early this year so you might want to start then). At AS the easter holidays were my two weeks of hardcore past paper sessions - I'd do like 3/4 papers every day then work on anything I got even slightly wrong. It was also the time when I focused on things that I completely didn't understand. In the end, though I felt dead (and, admittedly, had to take a few days off because I felt like my life didn't make sense haha- mental health is important so if you don't feel like working and it isn't because you're being lazy, then DON'T WORK!!!), I ended up with 4As at AS so it was definitely worth it and it definitely worked. To summarise: you want to be doing some work everyday (you can take sunday off if you want), up to 2 hours not including homework (and try to use your study periods, if you have them, at school to actually study!!), start proper hardcore (as in no life just revision) revision in late march/early april (which should coincide with the easter holidays). Good luck!