What have you been doing in the past? Which subjects are you taking? In maths, If you're aiming for a 9, you need to make sure that a) you are dropping almost no marks in the first 70% of the paper and b) you are capable of getting all or most marks on the last few questions that are especially difficult and set to discriminate between grade 7, 8 and 9 students. So to do this, you can set out a practise block where you quickly complete the first half or so of the paper (this should be second nature and easy to 100%), then the second half where you have more time to explore the trickier questions that will push you up to the grade 9. My advice for the sciences, English or other subjects would be different, so please specify which subjects you'd like to dial in on.