Jeff- what kind of warm ups are you using? length of sessions?
Our sessions are about an hour long. A few kids are early, some are late, so I let them play tag or whatever in the garage until we're all there, usually about 5 min after official start time. Then we line up, announcements, bow in, and begin. I usually start with some jumping jacks, squats, sprawls, maybe another calisthenic like pushups, mountain climbers, leg raises, mat drags, etc. The warmup varies from there; sometimes I have them do breakfalls and standing up in base. sometimes they do line jumps, shrimps, bear crawls, etc., sometimes we just get right into the technique/s of the day. So that's about from 3:35-3:45.
The technique portion usually lasts for about 15 minutes. By 4-:4:05pm I try to move them into a drill or game related to the technique they just learned. That lasts until about 4:15. Then the "assistant of the day" gets to pick the first general game we play. Most of them are all variants that trick them into wrestling or rolling without the pressure of an actual full out match. But pretty soon they will be ready for that as well, it's so great to see them develop.