Check your rear view mirrors every few seconds.... oops wrong test
My instructor gave me a bit of advice that worked for me - talk through what you are doing while you are doing it. For all the checks say them out loud - he will be certain then that you are checking everything eg startup, FREDA, rejoin etc - say them all out loud - if you are checking the map because you are unsure of your position tell him (he will have guessed) you will still get a pass if you go from unsure to sure. He's looking for safety and good airmanship, everyone makes mistakes - it's how you deal with them he is really interested in. Don't be afraid to ask the examiner if you are not sure of something - he is there to pass you and help if he can!
As others have said try and enjoy it - you will remember it for a long time but it is the best sensation when you park up and he shakes your hand