Ensure that you have a really good night's sleep and try not to let the lights put you off - they are very strong and you could easily be distracted. Also, ensure that each of your rounds are done on a separate page of your notebook. This might seem a trivial point but if you practice each round at home when the programme is on you will see what I mean. As the programme is recorded in real time - by that I mean what you see on the telly is what is recorded (apart from any technical mistakes such as lighting, sound level or verbal mishaps) - it is important that you complete each round when practicing in the thirty seconds, so stay calm and you'll do OK. Oh, and as chrissa1 mentions, learn your 75 times table.