Get out of the way of the kids energy
I have found that most kids have tremendous energy and enthusiasm as a natural part of youth. If left alone they will normally play the game very hard, with a tremendous amount of hustle. However, I have often seen coaches bring 15 kids into the locker room an hour before the game and force them to sit in absolute silence as the coach lectures about technical aspects of the upcoming game, or gives a pep talk. By the end of the hour the kids are often comatose, and they then play an uninspired game. Many coaches just like to hear themselves pontificate, which gets in the way of the natural enthusiasm and energy of the kids. While these coaches have good intentions to motivate the kids with long talks, the actual result is often the opposite.
While I insist on a quiet locker room for our pre-game strategy session, I keep these sessions to 2 to 4 minutes maximum. I try to only go over a couple of critical issues in the group setting, and then get out of the locker room and let the natural energy of the kids take over. I may talk to a couple of kids individually about specific topics, but when I address the entire team it is very short and direct. The kids generally can only remember and employ one or two things in a given game, so why tell them 50? As our team improves during the year I change the one or two points as needed.
There has been an interesting development as a result of my short lectures. After all the adults leave the locker room, the team captain and other older kids usually takes control, and the kids start talking hockey. It tends to get a bit wild in there, but the kids almost always come out ready to play. As a coach, all I had to do was get out of the way of the energy.