I also took my CPC exam last Saturday. I totally agree with the other comments posted as to having everything planned out the night before.
A couple other suggestions I have is call your proctor a couple days ahead. I called mine to find out exactly where to go and where the room location was.
The day before the exam, I had taken off from work, so for myself that morning I took a practice exam (through the AAPC) and reviewed over my notes and the guidelines in my books. About 1pm that afternoon, I called it quits. I actually did some laundry and even washed my car.....just other things to take my mind off of the upcoming exam.
On my way to the exam, I had some coffee, a small breakfast and some orange juice. I also once again reviewed over all the guidelines.
Going into the exam I had a bottle of water and a roll of Mentos and while waiting for it to start, I did some deep breathing exercises. I also made a point to sit up front so my back was to everyone else in the room, that way I could not be distracted by any of the others.
I too had also been advised to start at the back of the exam. I did not do this, and for my self I'm very glad I didn't. When the 30 minute warning of time was given, the back of the exam was where I was at. If there was any place in any section of the exam that I would have wanted to be "crunched" for time on, that was it. Most of those questions I did not have to guess on or look up, I just knew the answers.
The only other advice I can give you is know your books. I have mine tabbed like crazy. I was able to just go straight to where I needed to just by looking off of my tabs.
Hope this helps.....hang in there!