The most effective trick is to write down whatever you are going to do. You won’t believe how effective is it before you start doing it. Just write them down. I prefer pen and paper. This is one of the things you hear a lot and you ignore it by default. Start making it a habit my friend.

The second trick is to learn to write a simple decision tree. Stop comparing pros on cons on your head for all critical decisions. Also do it as much as you can for anything that requires mental energy to save your capacity as much as possible.

And third is, to learn simple meditation breathing exercise. (probably 1hr video tutorial on YouTube is enough to learn simple breathing exercise. You don't need more than that. IMO) Then use this exercise anytime you need to switch to diffuse mode. Do it anywhere you have to. Even during the commute to work. I know proper exercises has some sitting and environment conditions. But F.. that. You still get a lot of benefits. I’m sure there are more benefits in doing the whole thing in the right conditions. But even with minimum impact is enough.

And forth just because I saw taking a shower as a recommendation. Make sure your shower time is just a refresher. Don't think about anything during shower. Sign your favorite song if you can't stop thinking.