I don't know about primary, but in Secondary, this would be a big mistake. I think it matters less WHAT you do - what's important is that you are consistent and stick with something once you start it. If the kids sense you're making it up as you go along, they'll be looking for weak spots all the time. The first few weeks in a new school are often easier because you're an unknown quantity. After that it takes a lot of energy to get back on top once you've let things slip. You need to prioritise. Decide what you're going to deal with. Maybe stopping the talking over you to start with? Stop talking every time it happens and wait. Note the name of any child who sits quietly. At the end of the lesson, announce that some children have wasted some of your time and dismiss the co-operative kids. Keep the naughty ones back. If you keep the same kids back more than a couple of times, I'd ring home. Do the kids like you? It's often easier to win a class round if you get the good and not so good kids on your side because you take support away from the naughtier ones. it helps if you can catch the naughty kids being good and build up a relationship with them. Why don't the kids respect you? Are you too friendly with them? Or something else?