There's no way to do well on these exams without knowing everything related to the subject pretty thoroughly. Even if you goof up a maneuver, the examiner will know if you are on top of things or not and they may decide to let it go if they can tell you are just having a bad moment. Be honest, thorough, and careful and you'll do fine. The only trick I can think of, which really is not a trick, is to take the airplane to the airport you are testing for a trial ride the day before if possible, better yet the morning before the checkride. Do a warm up flight even if you think the guy is around and can figure out who you are and what you are doing. Don't go nuts but just warm up by running through some of the maneuvers alone. This will make a definite difference in both your performance at the ride and your confidence on the ride and in the interview.