Before the Exam
Before starting the exam I recommend you to sleep well and after that have a great meal.
Remember to Take a shower before the Exam and clean your desk.
Go to the super market and buy some food and drinks for you and if you have a pet like me buy to it too and clean the toilet.
If you have anything in your mind to do, do it before starting the exam.
Just clean your head!
Reload the machine, and if you smoke buy all the papers you need.
Just turn it off while you are Hacking! You being prepare for the real World :P
Before start the exam verify if you have backups of all virtual machines you need or tools, documentation, binaries. If you can afford a dedicated external disk to all you security/certification stuff, do it!