Stop sweating the small stuff and picking the right battles will help for sure. Don't get too entangled in situations and people who are toxic and think positive thoughts. If you can't avoid them, try to tune them out :)
I find that a lot of exercise helps! And doing things that keep your mind off stressful topics such as work. Meditation is a great one for me too :) You should try the app headspace for meditation - its great!! :D