We've all done it: eyed our neighbors on the pec deck or treadmill and compared our bodies to theirs. (I wish I had those biceps, or Why doesn't my butt look like that?) But before you start obsessing about what you see as physical inadequacies, take a look at the genetic deck of cards you're shuffling. Once you see what you can and can't change about your body, it might become easier to positively visualize your physical potential, says Howard Flaks, M.D., a bariatric physician in Beverly Hills who has a large celebrity clientele.

First, know your body type. You've heard it before: "There are three somatotypes, or body types: mesomorph, ectomorph, and endomorph," says Dr. Flaks. "Ectomorphs are thin, mesomorphs are more muscular, and endomorphs tend to be on the overweight side." Most people straddle two categories, such as a meso-endomorph, or meso-ectomorph. You might think you can figure out what body type you are simply by looking at yourself, but it's never really that easy. Ask your doctor which body type you fall under and you might just be surprised.

Another factor that affects your figure is bone size. Although a bariatric physician can give you precise information about your bone structure, try this quick guide suggested by the American Society of Bariatric Physicians: Wrap your hand around your wrist. If your fingers don't touch, you're probably big boned; if they just touch, you're medium-boned; if they overlap, you're likely small-boned. Obviously, you can't change the size of the bones you were born with, but you can let your bone size be a guide to your body weight. In general, if you're smaller-boned, you should be at the lighter end of the weight range for your height; bigger-boned folks can skew heavier.

Now that you know what you're dealing with physiologically, here are some ways to boost your mental body image:

Pick appropriate body role models. Men who grew up hoping to have Arnold's uber-buff build—but ended up slightly smaller—should work towards a more reasonable (but still healthy) body, like Lance Armstrong. If a woman were big-boned and muscular, she'd be setting herself up for certain disappointment by aspiring to look like Courteney Cox. Instead, she might want to aim for a body more like Gabby Reece, who's body type may be more similar to hers, says Ann Kearney-Cooke, Ph.D., director of the Cincinnati Psychotherapy Institute and a scholar at Columbia University's Partnership for Women's Health.

To improve your body image, boost your self-esteem, says Ilene V. Fishman, a clinical social worker in private practice in New York City who specializes in treating eating disorders. "Most body image problems are rooted in low self-esteem," she says. Noticing your beer belly and realizing you need to get to the gym is different from seeing your paunch as proof that you're a bad, lazy, or incapable person.

"Separate how you feel about your body from how you feel about other things that are going on in your life," suggests Fishman. Feeling dissatisfied with your career or relationship can make it easier to feel negatively about your body.

Look at your parents and grandparents for a guide to your body's potential. If you come from a long line of jockeys, football may not be your best sport. Pick an activity that reflects and highlights your talents, says Fishman.

Ask yourself if you've ever been attracted to or fallen in love with someone who doesn't have the "perfect" body. "It's important to challenge yourself when you get into the train of thought that you have to look perfect; you attract people and are attracted to people not because of perfection but because of a number of things," Kearney-Cooke explains.

Let other people know how they can support you. Tell them that it's not helpful when they tell you you're gaining weight or getting a belly. Instead, ask them to work out with you several times a week, advises Kearney-Cooke.

Give your self-esteem a boost. "Self-esteem isn't about men and women talking about how special they are. It's about success. Can you successfully handle your emotions, your goals?" she continues. "The better we can handle life, the less we make our body an exaggerated issue. It's easy to project the bad feelings you have about yourself onto your body."

Determine your body image by the positive body behaviors you engage in each day. "Keep track of the things you do that make you feel good about yourself," suggests Kearney-Cooke. That might be buying a healthy lunch instead of opting for junk food, exercising, moisturizing your skin faithfully, taking time to meditate, anything that makes you feel good about your body.