maths is about patterns
I have mastered the Du Gu Jiu Jian of maths, so I can handle
many questions with a few practice 
What one needs to do is to see common traits among questions...
to process, and to think, like a mini computer... and more
importantly, to be able to disect the questions to it's
bones...
What I realised when I taught APGP to students is that many are
boggled by the long walls of text. But many can do the question
when I guided them to extract just the critical parts, i.e. first
term, common difference, etc... In short, ignore all the flowery
stories, and zoom in on the important points.
Additionally, for maths, you have to know little tips and tricks
on efficient checking and back-checking... Example for Partial
fractions, you don't check by re-doing the question if you don't
have the luxury of time... What you should do instead is to sub in
x=1 on both sides (or 0 or some other values) and show that it is
the same... Same for Binomial expansion, or even at times,
sequences and series...
Finally, for higher level of physics, there's a lot of maths
involved... The physics of it is to understand and extract the
critical information, then come out with the right physics
equations... After that, it's all maths...