Resist the temptation to cram. You know what you know, and burning the midnight oil is likely to do more harm than good.
Get your stuff together for the next day, including directions to the test location, and pack it up. Don't add to your stress level with last-minute pencil sharpening.
Select and lay out your outfit for test day. Go for comfort over fashion (it's a loooong test).
Set your alarm for 30 minutes earlier than you think necessary to allow for any unexpected delays.
Get a good night's sleep. You're as ready as you'll ever be at this point; work on facing the challenge well-rested.