Music is one of the few things that will lift my mood no matter how down I am. Have a playlist of certain songs that no matter how much shit you are dealing with it can reset yourself to a better inner state of being.

Binaural beats can help too as well as pure solfeggio frequencies. You need a good set of headphones for this to be effective. It is more of a forceful reset like using a tuning fork. I only use that if my mind is in overdrive and can't be silenced by music.

As far as pure thinking thoughts go. That has always been a challenge to me. Sometimes thinking about my family and my dog works, but honestly auditory works best when I can't reset myself from the inside on my own.