Create a brag book. Jot down any positive feedback you receive—from your boss, your sister, even your hairstylist. The exercise will feel goofy at first, but Clance says it's the best way to give yourself a concrete reference next time you're inclined to discount your strengths. "When I was starting out, I'd explain my success with the classic impostor line, 'I got here because I was in the right place at the right time,'" says Clance. "Once I started listing the praise I received, I realized chance had very little to do with it."
Be a mentor. Finding someone who looks up to you can help you realize just how much you have to offer—whether you're helping junior staffers at your company or young girls from a local Big Brothers Big Sisters chapter. "Mentoring was one of the best things I ever did," says Joyce Roché, author of The Empress Has No Clothes and former vice president of Avon. "Passing along your wisdom not only helps the next generation, it validates all the hard work you've done."
Don't spread bad press. "Years ago I signed a nondisclosure agreement with myself that any personal put-downs would stay between my ears," says Nancy Ancowitz, author of Self-Promotion for Introverts. "While a little self-deprecating humor never hurt anyone, if you speak confidently to others, you'll feel confident." Eventually.
Feel entitled. "I once read an article in which a prominent male television producer said he wouldn't feel bad if his project failed, because he was entitled to make a mistake," says Valerie Young, author of The Secret Thoughts of Successful Women. "That was an aha moment for me. I made a list of things I was entitled to do: I had the right to not know all the answers, the right to be on a learning curve, the right to be less than perfect. Once I permitted myself those mistakes, a huge weight was lifted."