Although you would like a nice answer to those questions, there unfortunately isn't one. I was lucky enough to score 40+ raw in all of those subjects, and how I studied would be completely different to the next guy who achieved the same 'feat', and then different still to the next person, etc.
You've really got to try your best, that's the secret. Don't get caught up in a 'bad' score (whatever that means to you), don't get caught up in class rankings, don't get caught up with the one kid who finished the course in year 4 and feels the need to let everyone know every minute they're awake. Just do the work at a pace you deem appropriate (I'd personally refrain from falling behind or studying too far ahead, but up to you), strive to improve at everything, and somewhat arrogantly back yourself to perform on the big stage. You don't always have to ace every assessment, you just have to do well enough.