[Y]ou don’t get healthy self-esteem from constantly telling yourself how great you are, or even from other people telling you how great you are. You get healthy self-esteem from behaving in ways that you yourself find estimable.

For instance, you feel better about yourself when you keep a difficult resolution, meet a challenge, solve a problem, learn a skill, or cross something unpleasant off your to-do list. And one of the best ways to feel better about yourself is to help someone else. Do good, feel good.

I had a friend who went through a period of tremendous rejection: she was fired from her job, she didn’t get into the graduate program to which she’d applied, and her boyfriend broke up with her. Everything worked out fine, and I asked her how she got through such a tough time. She said, “I was practically addicted to doing good deeds for other people. It was the only way I could make myself feel like I wasn’t a total loser.”

—Gretchen Rubin