Bad training is pointless, if you don't have any vigorous, flow and or focus then you might as well just let them run through the field. I have seen coaches allow kids to just run around the field and teach themselves while they sat and talked to everyone else and then would get angry when they lost games. I didn't get that. And to this day I still don't. Focus on your training and whne you are training make sure that is what you are doing. Come up with an excercise that they will be comfortable with and can get familiar with.
Have a schedule planned. It is normal to get off of the schedule, once practice is flowing, to highlight some points that were not on your schedule. If you are not prepared to teach the kids...don't expect them to be prepared to win.