1. Have confidence in your abilities. You've prepared well for this day, so know that you're ready for exam day. Trust in yourself and what you've learned over the last several weeks.
"Believe in yourself! Have faith in your abilities! Without a humble but reasonable confidence in your own powers you cannot be successful or happy." - Norman Vincent Peale
2. Stop worrying about the things that you can't control and start focusing on the things that you can. The amount of time and effort you've used to prepare for the CPA exam are all variables that you can control. You can't control what is asked on the CPA exam, so go into the exam with confidence and the knowledge that you are prepared and just do your very best.
"You must learn to let go. Release the stress. You were never in control anyway." - Steve Maraboli
3. Set realistic expectations for exam day. Of course you want to pass the CPA Exam on the first try, but things happen. If you don't pass, it's not the end of the world. You can always take it again after a little more preparation.
"Winners make a habit of manufacturing their own positive expectations in advance of the event." - Brian Tracy
Other blog articles that might help you before you sit for the CPA Exam:
How to Cope with CPA Exam Anxiety before the Exam
How to Cope with CPA Exam Anxiety the Day of the Exam