Some of it is things you will have heard before, but its really just what I found best from first hand experience.
- Don't worry about them. The hardest thing to do, but the best: when you come out the other end, you will be thinking 'why did I even feel stressed!?'
 - Sleep. Early nights, especially before exams.
 - Treat yourself. Woo! For revising and during the exam period: I got through a lot of flavoured popcorn doing this blog.
 - Revise.
 - Practise. Do every past paper you can find.
 - Teach someone else; the best way to learn is to explain to other people.
 - Don't be stupid (go to hospital/do drugs before your exam.)
 - Bring all the right equipment to the exam- you just feel so prepared and in control.
 - Start revising really early to lighten the load and get things in you long term memory.
 - Deep breathing, kept me calm, focused and stress free ;)