Creating calming pictures or images in your mind, or 'visualising', can really help you to relax.
Try the methods below and practise whichever technique works best for you, so that if the need arises you can use it during the exam itself.
First of all do some relaxation exercises. Then imagine yourself in a calm state while taking the exam. You feel purposeful and confident. You see yourself at a desk, in the exam room environment. You feel entirely at home and attuned to that moment, working effectively and concentrating well.
Now practise visualising this positive, clear, realistic image over and over again.
Create a scene in your imagination. Think of a scene - real or imaginary, and from any time - that makes you feel safe, warm, secure and peaceful, with no uneasy feelings. Make it vivid - feel the breeze, the warmth, picture the colours, hear the sounds. Practise visualising this scene as often as you can. When you want to feel calm then think of this scene and imagine it for a short while. Then return your thoughts to the matter in hand. The sense of calm should stay with you and enable you to cope better with whatever comes.