Biggest thing I have noticed with my initial CFI students is the need to RELAX!!! This Checkride is hyped up because of the difficulty and the low inital pass rate, but that causes a lot of students to get nervous and make a mistake because of that, and not because they did not know it. I am not saying not to study, but do not let it be all you do, take a break, get some fresh air, and relax a bit before the ride.