Pick Your Battles
Someone once told me, "It's not what you say, it's what you Emphasize that matters". Unfortunately, I can't remember who! Another way to think of this is "pick your battles". As coaches, we often see 50 things we want to change about our team or players. Its so tempting to tell the kids all 50 things. We may tell kids to pass more, hit more, play position, be aggressive, wear a tie, show up on time, etc. etc. etc.
If you have 50 "important items" to cover, you really have no "important items". As a coach you have to select one or two things to work on in a given game, or week, and emphasize these. If you see 8 things wrong in a given game, you have to select one, or at the most two, and then work on it at practice until you fix it.
For example, if my team just got smoked in a few games, and we didn't pass well, hit enough, play good defensive position, and our power play was awful. I will pick ONE of these and work on it the next practice. I may decide that we are going to fix "defensive position in our zone" first. This is all I work on at practice. I tell the kids once we get it down, we will scrimmage. During the scrimmage I blow the whistle when the defensive positioning is bad. It's tempting to cancel the scrimmage and work on something else, maybe 4 other things. But then we are working on five things, not one. And we seem to learn none of the five.
If our defensive positioning is no better the next game, we go back and work on it again. I just don't move on until we get it. After awhile the kids get tired of the same drills on defensive positioning, so they do them correctly so we CAN move on!
So, its not what you say, its what you emphasize that matters.