1. Be professional
Arrive on time and look the part. Be friendly but polite. The assessment centre is partly a social exercise, so do chat with the other candidates at breaks and over lunch. Be prepared to initiate conversations. While it's fine to make small talk with assessors, don't be over-familiar.
2. Get your hands dirty
Don't stand back and turn your nose up. Group exercises are designed to see how well you work with others, so make sure you take part.
Be enthusiastic and make an effort, whatever the task. Besides, concentrating on the task in hand will help you to forget your nerves.
3. Don't lose concentration
It's going to be a long and tiring day, so try to make sure you have a good night's sleep beforehand, as you'll need to stay alert and engaged.
Even if you are assured that the informal food and drinks do not play any part in the selection process, you should be careful not to gorge yourself.
It's best to assume that if you let your hair down too much, someone will notice.
4. Don't act a part
Be yourself, but be the most positive version of yourself. Try to relax and behave naturally.
You might even find it's possible to enjoy yourself despite the inevitable nerves, and a smile is more likely to make a good impression than a face frozen in fear.
