Some mental rules (for myself) in the bull market:
-always stay humble. never forget your roots, and never forget you are but a guest in this transitory life, which can come to an end at any moment. in the end, you will take nothing with you.
-help others as much as you can. you never know the difference your guidance can have in someone's life. the good things you do to others will return to you and stand by you.
-comparison is self-harming. there will always be someone better than you. be happy for them, not envious. be ambitious but also be very grateful. without gratitude, you are chasing something you can never have.