Few things here: Mistakes and errors are part of learning and running won't help that; again that assumes there was intent in the mistakes. Learning and repeating the skill (and other techniques) will help the learning process. Stop taking it like some personal attack and once that goes, it is amazing how things improve.
Disruptive kids who don't follow repeated instructions or have a bad attitude (this is different than making a physical mistake) can be handled in three strikes and you are out, once they have been told once to correct something: needs to be gone for the day, needs to be benched for the game, and needs to be kicked off the team. What happens at home is not your responsibility. It will eat you up, so let it go.
Making kids hate running or push ups makes things worse. Look, if you have time, go for the conditioning, but many of us don't have the time, but my drills will make you breathe, hurt, and gasp for air. I have another week to get ready for games, with only two hours a day practice....
The drill we use involves the whole team making the throw and/or fielding play, etc. in a row up to a certain number, or start over. This has helped us a lot.
Weight training is what college players often lack, BTW.
Well said.