Broken window theory is a policy of policing. If, in an empty building, a window was broken, then a couple of weeks later, several windows would be broken, then in a month there would be graffiti on the walls, until finally there would be squatters in the house. However, if the window was fixed that week, all the police would have to fix would be the occasional broken window. I like to explain this to students when they’re complaining about my complaining about them tapping their pens. You can read the wikipedia entry here: https://en.m.wikipedia.org/wiki/Broken_windows_theory
How I manage behaviour:
Give a three minute detention each time a student calls out, or talks during written work (written work is always done in silence). I write on the notes section of my phone a student’s name when they call out, then put an ‘I’ next to it each time after that they call out or speak out of turn.
Anyone with three or more minutes of detention time to serve are kept behind once a week. This may be a huge proportion of the class, depending on how well-behaved the class is/when in the year it is. If a student has called out ten times over the course of the week, they will serve a thirty minute detention.
Ensure you get into the habit of dismissing your classes very on time. Otherwise, all your students only serving three minute detentions will start to kick up a fuss.
Make this clear at the start of the year. You can also have a whole bunch of other rules (I’ve found Tom Bennet’s 10 rules cover pretty much every eventuality), but if you sweat the small stuff, the rest will follow.