Have a good breakfast – slow release carbs and protein rather than high-sugar!
Have a last-minute check through flashcards if this helps to settle your nerves, but don’t try and learn anything new;
Check that your calculator is set up correctly – if in doubt, reset it (your manual should tell you how to do this), or ask a teacher to reset it for you;
Try to remain calm as you go into the exam (this is easier said than done!) – but you have prepared as much as you possibly can by this point, and all that’s left to do now is demonstrate that to the best of your ability.