Dean,Heya. I don't remember all the details, but here are a few hints, most of which you probably already expect. The oral part of the exam took about 15-20 minutes as I recall. Definitely know what all the symbols and numbers on your sectional stand for and mean. Know the dimensions, restrictions and radio protocol for the different airspaces, and whether or not you can or can't enter MOA's, ADIZ, etc. Know the visibility and cloud clearances for VFR flight in those airspaces.
Also be able to answer all questions regarding the type of aircraft your testing in, i.e., fuel quantity, oil quantity, type and horsepower of engine, etc. Know your light gun signals in case of radio failure.
The Gliems Private Pilot Exam book and the ASA Private Oral Exam Guide were helpful. They aren't going to expect you to know everything, no one does, but you should be comptetent and have a pretty good grasp of the basics. As far as what to watch for... the advice I got at the time was 'don't bullshit the instructor. If you don't know it, tell him straight away'. That applied more to the flight test than the oral, but all the same I'm tossing it in there.
I say study til your reasonably confident in your knowledge and relax. It will probably be far easier than you are worrying about.
Good luck and let us know how it went.