Genetics play a big part — no potions or lotions will ever change the genetics of your skin. Stress is another detrimental factor; it can overdry already dry skin and trigger breakouts in oily or difficult skin. The secret to beautiful skin, then, lies in taking care of the issues you can control — getting adequate sleep, drinking plenty of water, engaging in physical activity. "Good skin is not just about what you put on your skin," Brown explains, "but how you conduct your life."

So think ahead. Be aware that both smoking and sun worshipping can age your face measurably. "My advice is to be your own skin expert," says Brown. "Look at your face in the mirror and see what's going on. If it's summer, your face may be drier on the surface — thanks to air conditioning — but oilier underneath. If it's the middle of winter, or if you're traveling a lot by plane, chances are, your skin is super-dry. The idea is not to have just one product or one daily routine, but a flexible program that makes your skin healthy, smooth and clear." Below, a sample routine.

Clean and clear
Start by cleansing dry or sensitive skin with a gentle, non-stripping gel cleanser. If you have oily, acne-prone skin, find a gentle gel formula that's made specifically for your skin type, and follow with a non-alcoholic toner. Those containing alpha-hydroxy acids (AHAs) work especially well to help smooth the skin’s texture.

Scrub-a-dub-dub
On days when you really need to exfoliate, use a gentle, grainy scrub (skip this step if you've got sensitive skin). If you've got oily skin, you'll want to exfoliate twice weekly, concentrating on blackhead-prone areas like the nose and chin.

Do the dew
If your skin is dry, use a rich moisturizer that absorbs completely into your skin. At night, use an even heavier moisturizing cream. And if you have any extremely dry spots, apply an AHA lotion all over your face and a richer hydrating cream on those areas. Remember, notes Brown, you don't have to treat your whole face in the same way. Oilier skin types should opt for either a gel, oil-free moisturizer or mattefying cream. Before applying your makeup, take a minute to brush your hair or teeth while your moisturizer absorbs.

Look, Ma, no hands
Without even realizing it, you may be wiping away makeup and adding oil and dirt particles to your skin to boot. Try to keep your hands away from your face during the day. Catch yourself if you pull on your eyelashes or rub your chin. "Habits like these are difficult to change," says Brown, "but both your makeup and general comportment will benefit if you stop."

Take it off
At the end of the day, start your cleansing process all over again. Brown recommends using a non-oily eye makeup remover on a clean cotton pad to wipe away mascara, liner and shadow. "Oily removers can aggravate eyes and cause makeup to travel all over your face, making it more difficult to wash off," she explains. Once your eye makeup is removed, use your cleansing gel to remove all foundation, concealer and powder. Then dip a Q-tip into the remover and run it gently over your eyelashes to eliminate any residual mascara.

When to go pro
"When things get serious and you can't handle a skin-care problem on your own," says Brown, "don't waste your time and money at the cosmetic counter — seek professional help." Glycolic peels or an exolift treatment (in which a liquid polymer is applied to the skin with tape, taking dirt and grime with it when the tape is removed) are two excellent in-office dermatology processes for troubled skin.