Radar
With the technique, Radar (Teach Like A Champion, Doug Lemov) you focus on scanning the room at every opportunity - including when you are presenting to the class and working with groups - to check everyone is behaving as you expect. No misbehaviour gets past you.
Why use this technique?
If students know you are constantly scanning, they are more likely to behave as they should be. The certainty they will get caught if they misbehave is the deterrent. If this is in doubt, students are less likely to worry about it, so more likely to misbehave.
Notes and tips
When you are presenting to the class, position yourself so you can see everyone. Avoid blindspots.
Sometimes, you might choose to stand the back of the room, to help see what every student is doing. This includes when you are presenting.
When working with a group of students, try to position yourself so you can keep an eye on the class as a whole.
Focused reflection
How well do you currently use this technique?
Is it a technique you will focus on developing?
If so, what are the key features you will focus on (things to do, and not do)?