The best thing you can do is to see if you can sketch graphs correctly and do elementary algebra. If you can do both of them then you will be alright.
This forum is full of maths behaviourist. Practice itself won't do anything.
The best thing you can do is notice how the questions itself is structured and try to structure your thought around that. If you notice in C4 you don't really need to do lots of calculations as it normally part iii normally follows from part i and ii. So if you can see how to use what you have previously worked out and know to solve the problem that would be good.
The best thing to do is try and see cause an effect of the question instead of just becoming Pavlov's dog.
P.S. Yeah, saying that this is hard to learn as I noticed that on FP2 but then still done worse then I should then I only really learnt it when doing FP4 which went really well, I think.