Not every team has a legitimate shot of winning a tournament, and the kids know that score. They're able to take a lot of this in better stride than we do when our egos get involved. Do this early so you can remind them later. Also, be consistent. If you start with calesthenics at the first practice, fo them every practice.
Kids get uneasy if they feel uncertain in their coaches.
Decide how you want plays made, then work on the techniques from slow-motion to fast speed. This works two ways. Set your IF and OF as early as possible. But be realistic. Theach them details of where you want them to be and how you want them to play there.