We see weight loss success stories every day: Your best friend shed the last 15 pounds after having a baby or your colleague dropped three sizes in a year. But nowhere do we see the amazing slim-down results as when Jillian Michaels goes to work. The Los Angeles–based trainer, 35, has helped men and women transform their bodies before our very eyes while inspiring people like you and me to drop a few at home. That's just one of the reasons why I'm thrilled to tell you that Jillian Michaels joined SELF as a contributor. This month, I'll be blogging all about Jillian's secret to success, plus how to tone up and eat right.

To kick it off, I asked Jillian to share her number-one tip for peeling off pounds. Her answer—no, not bringing people to tears or even smart eating (a "clean" diet is her MO… we'll cover that in future posts)—is that brainpower is the secret to lasting weight loss. Jillian is a magician for the mind, helping even the largest folks lose half their size and more. She makes people realize why they want to lose weight, no matter how hard it seems at the time. So I asked her: How do you change someone's thinking? How do you help them achieve lasting and life-changing success?

Here are her strategies:

Prepare to commit

"You need to establish what losing weight is really worth to you," Michaels says. "People will put in effort if the goal is really worth it to them." Start any weight loss plan the way you would a long-term project: Recognize that the process might be long and challenging, but the hard work will pay off. And go slow and steady—crash diets not only backfire, but the resulting scale fluctuations are bad for your health. Research backs her up! Riding the weight loss roller coaster can lower levels of "good" cholesterol and increase the risk for heart disease, reveals a study from the Journal of the American College of Cardiology. (I've discovered Jillian isn't only right; she's also correct.)

Create your vision

"A lot of times people will tell me, 'Oh, I want to diet,'" says Michaels. "Then I will ask, 'But what is it that you want?' And they'll say, 'I just want to be healthy.' But they often they don't know what that means. You need to ask yourself, What does healthy look like to you? What does it look like personally; what does it look like physically? You have to create a vision of what you're actually working for and become attached to it," says Michaels, who asks her clients to write down what their perfect life looks like. It could include a having house on the beach, driving a convertible or finally fitting into the skinny jeans they've been trying get on for the last 10 years. "Everyone is an individual, so you need to create a vision that is uniquely your own. Write down what the landscape of your life looks like in an ideal world on every level—career, physicality, well-being, the car you drive, the house you live in, your jeans, everything!—because it's all connected. Remember, your health will be the platform that the rest of your life is built on top of. When you're healthy and strong, you feel confident, and that's going to help you excel in every other area. Weight loss success depends on creating that vision. You have to bring awareness into your life so that you can change your behavior and create a reality that is happier and healthier in the long run.

Toughen up

Making the lifestyle changes you need to lose weight requires that you become vulnerable, Michaels says. It's natural to be afraid that you won't reach your goal, "but you need to build up resilience and self-esteem so you know you can endure setbacks." Having a clear vision of what you want will help (see above), as will finding a personal mantra to keep you going. Research shows most of us dwell on negative thoughts (e.g., I'll never be able to run a mile), downers that can derail your get-fit goals. For more stamina, create a happy-place code word like beach or a can-do mantra such as "I'm invincible!" Repeat it when resolve is low and you'll stop the urge to quit.. And don't be afraid to slip up. "Setbacks are an opportunity for learning and growth. It will help you change and become better."

Chart your course

Starting a weight loss plan without having an idea of how you're going to reach your goals is like "getting into a car without a destination," Michaels says. "You need to chart a path and build a road map." In fact, new research shows that making a fitness game plan can speed weight loss. Women who were asked to state their workout goal, imagine a positive outcome, list potential obstacles and design a specific strategy to beat those barriers added an hour of activity to their repertoire each week, researchers from Columbia University in New York City note. Jot down your exercise intention each night using "if…then" statements, experts suggest: "If I sleep in, then I will skip watching the A.M. show I usually have my coffee with and go for a bike ride." For a step-by-step eating and exercise program guaranteed to get you in super shape, join the SELF Challenge.

Make conscious decisions

Negative behaviors can be unconscious, whether it's eating a doughnut with your coffee or driving a mile to the store rather than walking. For slim-down success," you need to really stop and say, 'Hey, wait a minute. What's going to happen to my body if I eat this doughnut?' " Michaels says. " 'Is this doughnut going to get me closer to my goals?' Start being aware of every choice you make and how it will impact you." Taking responsibility can work in your favor. Dieters who believed they had the power to control what they ate lost more than those who felt they didn't have ownership of their eating habits, the Journal of the American Dietetic Association reports. Think about what you've learned from past weight loss attempts—good and bad. What worked and why? What didn't and why? You are your own best case study. And don't be afraid to reevaluate your goals. It's OK to step on the scale once a week, but also gauge your success by focusing on non-weight-related aims such as increasing your energy.

Want more tips on tackling your slim-down? Check out the Food & Diet section of Self.com for healthy eating news and advice.