Think Yourself Slim

2. Choose an Attainable Goal

"Studies show that most dieters expect to lose as much as four times what they really can in a six-month period," says Stettner.

Think smaller: Count on losing just 10 percent of your weight within six months, and focus on keeping it off for more than a year. But be careful about relying solely on figures. "A number on the scale isn't a goal; it's a measurement of success," says Bonnie Goodman, a psychotherapist based in Fort Lauderdale, Florida, who specializes in behavioral therapy. Instead, focus on behaviors you wish to change: to reduce your daily fat intake to below 35 percent, or to cut out your afternoon soda or vending-machine snack. Also, consider setting non-weight-related goals, such as entering a 5K race. The pounds you'll automatically lose in the process will seem like a bonus.