I've found the best approach to a meeting is once the group is promptly assembled at the scheduled start time, the first thing is to announce your appreciation for everyone's excitement. However, if you need to restore a teaching atmosphere, let them know that you will raise your voice to say a part sentence which the group then, in unison, must reply with the remainder. It very nicely got everybody back on track without targeting any individual in particular.
The second approach to any good meeting is to preview, view, and review. If you announce what is hoped to be accomplished during the current session, then that too helps keep folks focused. When the class is about to wrap up , review what's just been learned and give an enticing bit about the upcoming session, etc., reminding once again to be prompt. Of course, there should be intermittent breaks for questions about the current subject.
This developed after years in the education sector. Hope it helps.
Last edited by QuiltnNan; 10-06-2018 at 04:45 AM.
Reason: shouting/all caps