Hardest thing to do is convince shooters to not sky bust. Only way I found to do it was limit the number of shells a shooter was allowed to take out into the field. If they have four boxes they will burn through them and want more. I limit shooters to two boxes. After that they can walk back to their truck and get one more box of shells. We call it the walk of shame. But after we did this the number of dove taken per shell went up almost 50%. Not 50% hit rate, but from the low teens, sometimes the very low teens to about 25%. Some did a lot better. Also I have them walk out 25 paces and see what that distance looks like. Thats a decent kill zone for most.
Some shooters will double their number of dead birds if they just let birds come in ten yards closer. Inside 20 yards Im a 95% shooter. Others might be a 50% shooter. Plus the number of lost dead birds goes down the closer they fall to the shooter. Some shooters dont shoot enough to hit much more than 20% of what they shoot at any distance. So I tell them if you want a limit you must hit 20% or more. Thats not a high bar on early season Doves.
What I really like to do is sit next to a young shooter. Explain to him whats too far. Coach him until he starts hitting birds about half the time. Their smile, when they hit one, make it all worthwhile. I think, hooked another hunter.