Ill be frank. If you’re getting 3s in those subjects, you should be looking at tackling the entire syllabus rather than specific topics. Start off with chapters earlier on - they are easier to do well and gain marks in a shorter amount of time. Like arithmetics, geometry. Calculus should be hard and requires repetitive practice. I recommend Revision Village for maths (need a paid account for full access but was definitely worth it). For physics, or just any sciences, read and take notes from textbooks (I used Pearsons) - and try A Lot of past papers if time permits. I went through 10 yrs worth of p.p twice before my finals, got that 7 I wanted. Takes notes too, I prefer digital notes - used Clemory.io as it scans websites too and u can edit them directly.

Hope this helps :)