Here's what I do:
Two nights before the exam, do all the performance figures you can. Do your W&B, do your x-c planning, and do some polish up studying. "Chair fly" all of the maneuvers. Organize your stuff and put in your flightbag.
The night before the exam double check your bag to make sure everything you need is there. Put it back in the bag and have a beer (as long as you're of age and it's at least 8 hours before the exam). Go to bed.
Get up early the morning of the checkride, eat a good breakfast. Head to the airport and finish up all of your performance data, get the logbooks and look through them to have an idea where all important inspections are. And take the exam.
I find that I'm not going to learn any new stuff the night before, and cramming just makes me even more nervous.
GOOD LUCK