If your teen years were for rebelling and your early to mid 20s were all about exploration, then your 30s should be about learning from old lessons, putting bad habits to bed and setting new wisdom to work for you and your future.

No matter what your age, the sooner you start these seven significant steps, the better:

1. Ditch dieting for sustainable lifestyle changes. Fad diets don't work. By the time you reach rour 30s you've heard this a million times-and probably learned it for ourselves the hard way. What you may not realize is that, really, diets in general don't work. The only way to reliably lose weight and keep it off for the long haul is to eat mindfully (that means paying attention, savoring and stopping when you're full), and to eat healthfully, focusing on fresh or freshly frozen vegetables and fruits, lean proteins, whole grains and non-saturated fats, and avoid the five food felons-added sugars and syrups, any grain that isn't 100 percent whole, and saturated and trans fats.

2. …And get comfortable in the kitchen. One of the best ways to know that you're eating according to your plan is to cook for yourself. That way, you'll never have to guess what ingredients you're putting in your body and you can control the portions and flavors yourself. Need help making the transition from take-out slave to kitchen queen? Start with these articles on how to have fun with cooking and turn cooking into a habit and a hobby instead of a chore.

3. Set a bedtime. Think bedtimes are for kids? Think again. When you leave for college or get your first apartment, you might think that going to bed whenever you darn well feel like it is a hallmark of adulthood. But the truth is just the opposite. Setting a regular sleep-wake schedule helps you maintain a healthy body weight, manage stress and keep your skin glowing and wrinkle-free.

4. Try yoga or meditation. Meditation helps maintain your brain cells and preserve memory-related functions, and the stress-reduction component helps prevent such conditions as depression and anxiety disorder. To meditate, all you need is a quiet room. With your eyes partially closed, focus on your breathing and repeat the same word or phrase over and over again-it doesn't have to be "ohm," but it's a good place to start. Much like meditation, yoga does a lot for you without looking like it-and there's a meditative aspect to it, too. Yoga increases your flexibility, builds strength, lowers stress responses and blood pressure and contributes to longevity. It's also is a great way to work on number five.

5. Practice balance. Falls and broken bones in old age are something we don't tend to think about until, well, old age-or worse, when we fall. But recent research suggests that the time to think about falling is well before it happens, in your 30s and 40s. That is when you need to start improving your balance, beefing up the balance trifecta of vision, inner ear and proprioception (sense of body position) before their inevitable erosion begins after 40. Try yoga poses that focus on balance-such as tree pose, triangle pose and high lunge, among many others-or stand on one foot on an unstable surface, like a pillow or a thick 1970s-style shag carpet, while swinging the other leg back and forth.

6. Use sunscreen every day. The sun is the absolute numero uno skin ager. You're supposed to get about 20 minutes a day of sun exposure (when the sun is low enough that your shadow is longer than you are tall) to provide your body with the vitamin D it needs. But you should limit that direct exposure to your body, arms and legs, and use SPF 30 sunscreen on your face and the back of your hands every day. This will prevent the UV damage to the collagen and elastin in your skin that causes wrinkles and age spots. We also take a supplement of 1,000 IU of vitamin D3 a day, as maintaining adequate levels of D3 decreases the chances of breast and a number of other cancers.

7.…And retinol every night. While you're at it, your 30s is a great time to add topical retinoids (a form of vitamin A) to your nightly skincare regimen. It's really the only thing you can put on your skin that can repair sun damage, giving you smoother, less wrinkled skin. Topical vitamin A increases the stretchy elastin fibers, the hearty structural collagen and the natural moisturizer hyaluronic acid in the skin. Vitamin A is found as retinoic acid (Retin-A, prescription only), retinol or retinyl propionate. All of these forms work, because your body can transform one into another. Sun light destroys vitamin A-and worse, turns topical As into skin-agers-so you don't want to put it on in the morning. Use it at night when it can do the most good.