Read the question and try the problem solving method. Steps 1 and 2 have been done, try step 3 and 4 (5 and 6 don't apply). Still stuck, put the question aside and ask your friend or teacher for help.
Do as many of the past question that you can before you sit the exam, label each past question carefully. Ideally you will finish all the past papers.
By the time the exam comes you will have quite large topic folders - where you can sort them into questions from the two papers eg paper 2 and paper 4 or paper 1 and paper 3. I recommend storing them in ring binders separated by dividers under each topic as well as having a ring binder containing the past papers stored in chronological order.