From someone who just passed theirs yesterday with 0 minors (</ egoboost), I've got to say that it's all about confidence. They like people who show they can drive by not completely coming to a halt at a junction if you can see it's clear to pull out, and other stuff like that. And make like an owl and look all around you as much as possible, you can't be failed for being too observant. This ones very well known but you might not know it: The 5 Second Rule. I spent my whole test counting to 5 over and over again, every time you get to 5 look in a mirror or the speedo, the rest of the time look where you're going. Obviously this help to prove your observation, but it has the added benefit of calming you down through repetition.
Oh, and I think that the fact I was talking to my examiner the whole way through the test helped her miss some of the minors I might have picked up had I been silent...
Good luck, and remember it's not like it's the end of the world if you fail.