Know your exam
Be sure that you have looked into the past papers.
It will make sure that you are well prepared for the type of exam you will be sitting for, whether multiple-choice, short answer, or essay.
Know what you are expected to do: Example, how many of the questions from each section will you have to answer? Of course, you will still have to read the instructions on the question paper itself and make sure that they are all the same, but it will help you to feel very comfortable with what will be expected.
Even more important is that, you have to make sure that you have practiced the right type of questions, and you know what will be expected of a ‘good’ and ‘bad’ answer.