Know the paper
I really recommend knowing the layout and history of the paper from year to year. Both Studyclix and examinations.ie have an extensive examination material archive on their sites where you can access all exam papers from 2005 onwards. Also, look at the marking schemes for each exam, this will give you a feel of what the examiner is looking for in answering the questions on the paper.
Stick to and practise the timing for each type of question on the paper in the run-up to the exams. If you go over the time allowance, move on to the next question and go back to the incomplete question at the end of the exam if you have time.