Pull out some of your old exams throughout the year, and go through them again. See if you got the same things you got back then wrong again.
We're testing two things, whether your still making old mistakes, or brand new ones.
Once you've figured out your mistakes, we write them all down on a page. Go through them 1 by 1, not only doing past papers/exercises where the questions are manifested but see how they relate to everything else you've learnt.
The biggest problem i think in most students doing bad in school-math is they learn about each topic independently. They see math topics as completely different topics. When you start linking things in your head, association kicks in, and the same style of memory that remembers the location of almost every shop in your suburb, is put to use for math.
So basically i'd recomend.
-Isolate errors-
-Do exercises and just general investigation on the problem until you can consistently solve problems of the type.
-Then the step that eliminates the whole "I could do this when we did the topic in class, but when revising i have no idea" 'The linkage'
-And then if your feeling cocky and think your new found self-esteem is un-dentable go do some challenge questions.
Doing this, for every "question-style" you have got wrong, and then going over a past paper, and repeating it for everything you got wrong, will get you 100% in the exam (but more importantly, integrate whatever you've learnt into yourself permanently) (Bar misunderstanding what the questions asking, and careless mistakes)
