This is for football but can be used in any sport. From our very first practice we have had great success by micro-managing every minute of practice. At the start of practice all coaches are given a schedule with their assignments for that practice. The key to this is small groups. On our teams we usually had 30 kids 7-8-9 years of age with short attention spans. If they were standing in line for any period of time they started horseplay and lost focus. Also doing the same thing for any period of time became boring. We break down to 5 groups of 6, sometimes larger for certain drills, but the short groups moving from station to station worked great. You might be teaching the same thing in every group but in a different way and the kids never get bored. This also works in baseball. On our football team we have drills, water breaks etc scheduled to the minute.