At the point your exam begins, you are a pilot. You are not a student and rules that apply to students do not necessarily apply to you.
Have reference material with you. POH, AIM, even your manual (jeppeson, Rod Machado's private pilot, etc.) Study but know you can look up if you needed. Don't BS. The examiner wants you to know the answer or know where to find it. Of course, most of the time, you'd better know the answer.
For the checkride, be nervous as hell

I did have some of the best landings I've ever had with the inspector.

. Worked for me, I'd trust the advice of the other posters on this one.
Fly during marginal weather.... This is especially helpful under the hood. Just when I was about to drift out of tolerances, the examiner had me change directions as we were about to fly into a cloud. It also helped in my "diverting to another airport" scenario. The more difficult diversions had clouds. We ended up aiming for the easier one.
During my training for unusual attitudes I was presented with scenarios of 'speed is slow but increasing' or 'speed is fast but decreasing'. The examiner presented me with a new one, 'speed is slow but decreasing'. Almost did the wrong thing here.
If the VOR needle is jumping around, approximate by aiming for the middle of the swings. The Newberg VOR does that, I was told.
Always keep a landing spot in mind. Don't forget to look on BOTH sides of the airplane for suitable spots. Mine was less than ideal due to trees but I made it.
Don't let the examiner distract you during critical phases such as landings.
Do what you think is safe. Going around on a marginal approach is not considered a failure in landing but an exercise in good judgement. Going around multiple times may make the examiner question your ability. Going around 5 feet off the deck... The chief pilot informed me that if, in this situation, I was told a deer bounded on the runway to just land because going around for an imaginary deer would be a lot more dangerous than landing. He'd back me up on that one if it came to an argument.
The examiner will tell you if you fail BUT, you can elect to continue with the check ride. As I was told, the rest of the checkride can count towards completion. Did I misunderstand that?
What's the worst thing that can happen? You fail the checkride and have to do it again or, at least, the portions that you failed on. In the off chance that happens, you'll be a better pilot the second time around.
Craig.