My main advice would be don't take it for more than it is. Just a test, not the end all be all of the world. Being nervous during the test doesn't help you in any way, shape or form.
I'd also advise taking it easy the day before the test. I tried studying, and it became obvious that it wasn't going to help, and I was glad I could take a bit of a break and just kind of rest for a bit. Of course, this isn't good advice for everyone.
Along these lines, plan your morning coffee at a time when you will have a chance to use the restroom for your post-coffee whiz. Seriously, the whole week before, I would drink coffee + 1 glass water and see how long it took me to need to pee, then I planned on drinking my morning coffee X hours before the test so I could make sure I didnt have that urge distracting me.