What’s one simple habit that actually improved your productivity?

I’ve been trying to be more productive lately, but instead of big changes, I started focusing on small daily habits. Surprisingly, even something simple like setting a clear to-do list before starting work made a noticeable difference for me. Wacky Flip 
It’s not perfect, and I still get distracted sometimes, but having a basic structure helps me stay on track more than I expected.
I’m curious that: What’s one small habit or change that actually helped improve your productivity? Nothing too complicated, just something simple that worked for you.