The showmanship patterns and maneuvers are very technical and that question could be answered with an entire book. The biggest thing I stress in showmanship is PRESENTATION!! That is what showmanship is really all about. It is about the confidence and presence you have. Confidence is the key to showmanship. Everything you do must be sharp, direct and confident. You are selling yourself and your horse to the judge. If there was the most important aspect to showmanship that is what it is. Work on that polished, confident and forward execution and presence. The details are important, for you need a good pattern, but you have to learn how to be confident.
A good forward walk, confident, cover ground, sharp
Trot is same
Eyes are always up no matter what you are doing in a showmanship class or pattern. And always remember to show to the judge the entire class!! As long as you are in the arena you are being judged.