Run through the engine fail checks - and corrective actions (mags/fuel/master/carb etc) in your mind a few times? Getting those in nicely during a PFL always gets brownie points.
Above all, try and relax enjoy the skills test (I know thats hard to do, but it does help if you can). At the end of the day the examiner wants to make sure you're safe, and you must be if you're doing the test!!!
Hope the weather is okay for you and all the very best
. I'm due to test fly an aeroplane I might by a share in, so am crossing my fingers for a vaguely flyable day tomorrow too.