"By having a diet that is very rich in greens [and/or] supplemented with green pounder drinks you can get in health food stores ... you raise your body's PH balance, which leads to anti-aging," says dermatologist Dr. Jeanette Graf. On the other hand, acid producers like caffeine, alcohol, dairy and cigarette smoke need to be limited as they have the opposite effect.

When you're exposing skin to city dirt and grime, especially during sweat-filled summer months, a blemish (or handful of them) is bound to happen. Don't panic or pick; you'll get scars. Patiently wait it out and cover it with a sweat-resistant formula: Moisturize a clean blemish with a skin salve or balm like 100% Pure Organic Healing Moisturizing Balm, $25, then brush on concealer (like CHANEL Correcteur Perfection Long Lasting Concealer, $40). No time to wait it out? Head to your derm for a hydrocortisone injection, which can safely deflate a monster zit within 24 hours.

Stress is a no. 1 factor when it comes to how your skin looks. Since it's hard to get a good night's rest in a bustling city, and smog already causes skin cells to react as if they are facing stress, getting a good night's sleep becomes doubly important (not to mention a cure for a sallow, sleep-deprived complexion).

When your skin isn't cooperating but you need to fake a healthy glow, rely on a prebase serum or gel with light reflectors in it (like CHANEL Le Blanc de Chanel Sheer Illuminating Base, $45). Used as a primer, its shimmery, iridescent finish gives skin of any age a glow so subtle that no one will know it's not real.

In addition to regularly exfoliating your face to fend off dry skin (super important during winter months), don't forget to scrub your lips. Chapped lips are one of the first signs of a much larger-scale dehydration. Exfoliate with a sugar scrub like The Lip Scrub by Sara Happ, $24; wipe the scrub with a washcloth, then moisturize lips with a rich balm or eye cream.