Look back and remember one sentient being that needed you. Perhaps, you tended to or interceded in their behalf. Maybe you rescued a dog, supported a family member, neighbor, or even a stranger.
Think about a time you helped one sequence of events along or changed one life for the better. Appreciate you existed at that moment to aid another.
When I answer the phone to listen to a companion, take a meal to a sick friend or exchange niceties with people in the world, my day is brighter.
We accept our own worthiness as we give out kindnesses.