Don't Answer
Don't answer messages when they arrive. Answer messages when you want to.
This is one of the strongest forms of willpower and self-control.
Imagine someone texts you and you automatically reply, but do you really want to do it? Before I started thinking about this, I used to do the exact same thing. But for a few days, I didn't write anything to anyone online, and I felt more relief than I could have imagined. It turns out that going online every day with the expectation of answering people's messages is absurd, and it's not mandatory to reply immediately. If something is urgent, there's a phone call, and that's that.
It's a simple action, but very effective and "non-routine".
I can't stand small talk