My examiner was very relaxed - I'd got lots of things ready to show him like the 214+215, print out of NOTAMs for the route, W&B and performance calculations etc, but while he looked at a few of them he was fairly uninterested in the rest - I think the fact I was offering them was enough to show I knew what I was supposed to do!
He did ask me to talk him through the aircraft documents, which was fine, and then we were off. I'd already pre-flighted the aircraft before he arrived (to make sure it was OK etc), though I was expecting to do it again as a demonstration to him, but he was happy as was.
After the actual flying parts, he asked me a few questions about the aircraft (a C172 in my case) - things like what type of flaps it had etc, but it seemed to me he was doing that mostly as a 'ticking the box' exercise rather than actually being worried about my answers!
What I would say, is remember the examiner is not expecting perfection, they just want to make sure you're safe - as such if you realise you've got something wrong or whatever, just say so and you'll probably get a chance to do it again, there are very few things you can do that will be an instant fail...