I don’t know the ages you’re teaching, but then again I don’t think it matters much if we’re talking principles. I teach 3, 4, and 5 year old physical education, here’s some of what I do, off the top of my head...
Keep your expectations reasonable. Kids, and even adults, are going to talk and laugh at times. No one should be expected to be absolutely silent the whole time. Let kids be kids.
Know what to ignore and what to address. That kid of goes with the previous part. If you’re telling them to stop every little thing, it loses its effect. You’re just that guy making noise after a while.
Keep them busy. Idle time is when most issues arise. It’s had to talk and/or distract someone when their hands and feet are going and they’re focusing on doing something.
Keep proximity to kids who are known to distract others. The further away you are from them, it’s like the more they think they can get away with.
Raising your voice/stern voice has its time and place, but be selective with it. Like the above, the more you do it, the more the norm it becomes and eventually loses its effect.
Make sure there’s enough positive feedback and praise. If the kids don’t hear they’re doing things right, they think nothing is going to be good enough, so why bother.
Set clear boundaries and expectations, and be consistent in enforcing them. But keep them appropriate and realistic. Don’t ever threaten something you don’t intend or aren’t allowed to follow through on. Once you state a consequence, you’ve got to follow through, otherwise you lose all credibility. Keep the consequences realistic.
Give warnings, but very few. If the consequence for talking out of turn is 10 push-ups, for example, don’t warn them 10 times. One or two warnings is sufficient before you enforce it. But again, be realistic in your expectations and consequences.
The ages and any known issues will determine your expectations. You can’t expect a kid or bunch of kids with adhd to be 100% focused and on task 100% of the time. More kids have issues than parents will admit to, to you and often enough to themselves.
I’ve worked with people that have expectations that are just way too unrealistic. I worked with a guy who just couldn’t get past the concept that 4 year olds couldn’t always run on the perimeter line without occasionally cutting across the gym, passing other students, cutting the corners, etc. He’d start yelling and having them sit out. He’d have them keep doing running until they did it right. When he won, what did he really win? All he did was spend half the class trying to get them to do something that was meaningless in the grand scheme of things. Another guy couldn’t handle 5 year olds not doing sit-ups and push-ups properly. He went through the same frustrations.
If kids are spending more time being punished or told what not to do than actually doing what they’re their for, chances are pretty high you’re expecting too much. That’s not always the case, and there’s typically more of that when the group is a new group, but after a short period of time, they should be under control.
Sometimes it’s a “classroom management” issue. Other times, it’s simply a lesson planning issue. Sometimes, but rarely, it’s just a bad mix of personalities in a class and nothing’s going to work. It’s rare, but it happens. Just don’t let that be an excuse.
Respect isn’t demanded, it’s commanded. Respect isn’t given, it’s earned. Even if kids have no idea what any of those words mean, they certainly know it inside and out.