Think and focus on things you're looking forward to.
Avoid thinking of your worries.
Separate yourself from toxic presences, which I personally think is usually the biggest triggers of bad mood and temper in many people.
Enjoy any good things, even the little and menial ones, as you will never know what impending distresses could descend upon you in a moment.
If I fail to adapt to the fault of others, it is my fault.
Succinct is golden.