I am year 6 (only ever been in primary with 6, was
a decade in secondary too)
Start off speaking quietly. If you start loud, you can only get louder.
Mark as you go. Do at least 2 tables in class.
I find getting in earlier is more productive than staying later. I get in early, it's quiet, the photocopier is mine, there's no one to chat to.
If you know you have a heavy detailed mark in one subject/class, plan another to be self or peer marked.
Use your seating plan. Feel free to move them. They take time. Don't put your prize shouty naughty boy at the front, they have an audience. Stick them at the back, maybe facing a wall.
Even older kids like stickers and prizes.
I have a chart on my wall with spaces for best listener, politeness, kindness and teamwork. I put names up as I go on the half term and leave a pen there for the students to add names. Prizes at the end of half term. Surprising how it works, and it's often the kids who slip through the notice net that get on there.
Wait for quiet. Wait some more. Wait longer than you thought possible. The old one of writing QUIET on the board and losing some of break works.
Ring home. Not just for naughties, but for goodies. A phonecall home to say their child was focused,kind, great at something etc does a lot. I sometimes send postcards home. Better than certificates, which are often daft or unobtainable. This week I rang a parent to say how impressed i'd been with their kindness and maturity in an incident and the mum responded so gratefully. It often.opens up whole conversations because a)they are pleased and b) it's more individual.
This doesn't apply in secondary, but remember in primary, your drawing and art skills are always brilliant, and you get to feel like Tony Hart / Van Gogh.
I get asked crazy questions all the time and if I don't know the answer I will say that and find out. And then tell them. It models learning really well. This week I didn't know the calorific intake and need of the Siberian Nenet people. I am finding out. Not knowing is a marvellous example. Sometimes you can do pretendy not knowing and they LOVE finding out for you.