Practice these three things and your happiness level goes up: 1) Gratitude 2) Forgiveness 3) Giving
These are not mere words to display in a quote on top of an inspirational, rainbow-filled background. “Practice” them. Look for opportunities to DO these things.
You’ll notice in your own experience that it’s impossible to be simultaneously grateful and feel lack, to forgive and clench the poison of a grudge, and to devote some of your resources to someone in need, and still feel scarcity.