[dantheman0207]

Meditation is the best thing for this. I also like to use a heart monitor to measure my HRV when meditating - it gives me an idea of my physical & mental performance today compared to my baseline.

A physical workout can also be good. Lifting weights (consistently!) makes a difference long term in my mental performance, but the biggest difference for me is going for a run. The runner's high is real, once you get to a place where you're comfortable with the distance you're doing.

There's scientific research that keeping a journal has a positive effect on your mood. Especially if you explicitly try to write about gratitude.