I agree. Practice is great. But make sure your practice relates to game situations. Dont just hit fly balls. Hit hard shots through the infield glove side, arm side, right at them, line drives right at them, line drives in the gaps, high shots, bombs, cans of corn, etc etc. And then understand when there standing out there knowing your going to hit them a ball its totally different than a live shot off a batter. So have them play everything off a bat in bp like a game situation. Working on reads, learning to see how it comes off. Give them situations. 2 outs runner on 1st. 2 outs runner on 2nd. No outs early in the game no one on. Etc etc. Teach them approach many times can be dictated by score, baserunners, etc etc.
Drop steps, cross overs, reads, routes, - and the situation can dictate the approach many times. It is not as simple as just hitting fungos to guys standing in the outfield or telling guys to shag bp for practice. BS practice is worthless and sometimes worse than no practice. Proper practice, proper instruction, experience, thats where it is at.