Illustration: Rebecca Chew

Step No. 1: Cleanse and Exfoliate
Cleansing, crucial to keeping your skin healthy, removes dirt, pollution and the dead skin cells that can make your complexion look dull. So you want to do it right. What are the most important things to look for in a cleanser? It should be a nonsoap formula, gentle, and—most important—suitable for your skin type, says Francesca Fusco, MD, assistant clinical professor of dermatology at the Icahn School of Medicine at Mount Sinai. To find your skin type, wash your face with any nonsoap cleanser (Cetaphil Gentle Skin Cleanser is a good choice). Wait about an hour. If your skin feels tight all over, you're dry: You'll want a creamy, milky or micellar no-rinse formula (try BareMinerals Clay Chameleon Transforming Purifying Cleanser, Clarins Cleansing Milk with Alpine Herbs or Garnier SkinActive Micellar Cleansing Water). If your skin feels tight on your cheeks but not on your forehead, nose and chin, you're combination: opt for a foaming cleanser (like Olay Foaming Face Wash—Combination/ Oily Skin). And if you face feels greasy or looks shiny, you've got an oily complexion: Consider an exfoliating cleanser (we like Bioré Baking Soda Pore Cleanser) or one with salicylic acid (such as Dermalogica Clearing Skin Wash), says Kavita Mariwalla, MD, clinical assistant professor of dermatology at SUNY, Stony Brook. Keep in mind that except for acne cleansers, which penetrate pores on contact, treatment cleansers with antiaging ingredients aren't effective: They're not on your skin long enough to make a difference, says Ranella Hirsch, MD, a Boston dermatologist.

"I tell my patients to cleanse differently in the morning and evening," says Fusco. On waking, a water rinse is enough for most complexions; if you're oily, use a nonsudsy or micellar cleanser. Before bed, when you want a more thorough cleansing, use your fingers to wash with lukewarm water and a dollop of cleanser in a circular motion. Add a little pressure to stimulate circulation, says Mona Gohara, MD, associate clinical professor of dermatology at Yale University. A cleansing brush isn't necessary, but can be helpful if you wear a lot of makeup—the oscillation of the brush can dislodge makeup and dirt from your pores, says Fusco. A brush also exfoliates, removing dead cells from the skin's surface, which diminishes dullness, encourages a healthy glow and helps treatments penetrate better, she says. (Get Clarisonic Mia Fit.) Hold the brush so it "floats" over the skin; scrubbing can cause irritation. Another way to exfoliate: Incorporate an alpha hydroxy acid (AHA) into your routine. AHAs loosen the "glue" between skin cells, so the dead cells slough off more easily, revealing smoother skin that reflects light better and leaves you glowing. In the morning right after cleansing, try an AHA lotion or pad (Elizabeth Arden Skin Illuminating Retexturizing Pads, 5%, if you're a newcomer; Cane + Austin 30% Miracle Pad + for AHA vets). To avoid potential irritation, use the AHA only once or twice a week until you know how your skin reacts.

Face Time: Females between the ages of 16 and 25 take an average of three selfies daily, which adds up to 48 minutes per day in front of the camera, what with the posing and grooming, according to a survey commissioned by FeelUnique.com.

Step No. 2: Treat
In the morning, apply a treatment serum that contains antioxidants like vitamins C and E and a moisturizer that contains a humectant, like hyaluronic acid or glycerin.

Antioxidants fight free radicals, the molecules that damage the DNA in healthy skin cells, and have been shown to encourage collagen production. They also help mitigate the damage from UVA and UVB rays and reduce the appearance of dark spots, says Fusco. Look for a formula that contains ascorbic acid (vitamin C) and comes in an airtight pump or tube. For best results, use a mix of antioxidants, says Cheryl Karcher, MD, a New York City dermatologist; for instance, you could apply a serum that contains vitamins C and E (try SkinCeuticals C E Ferulic) in the A.M., and a lotion with an antioxidant such as selenium, zinc or green tea in the evening (like Dr. Brandt Xtend Your Youth Face Cream).

Hyaluronic and glycerin are two of the best ingredients for drawing moisture into the skin. Moisturizing is key because it helps support the skin barrier, which can be compromised by cold air, dry heat and other environmental insults. When the skin barrier is compromised, you're more vulnerable to irritation and infection, says Gohara. Keeping your skin well hydrated also temporarily plumps it up, diminishing fine lines and wrinkles. (Try Olay Regenerist Micro-Sculpting Cream with SPF 30.)

For nighttime, the gold standard treatment is a retinoid, the vitamin A derivative that's been shown to increase collagen production, regenerate elastin, unclog pores (reducing their appearance) and stimulate cell turnover (helping eliminate dark spots). Great news: There are many formulations of prescription retinoids and their over-the-counter versions, retinols, so it's much easier than it used to be to find one that doesn't irritate, says Fusco. If you've never tried one (or if you have sensitive skin), start with an over-the-counter retinol; it will be less potent than a prescription and not as likely to cause redness and flaking. (Get PCA Skin Intensive Brightening Treatment: 0.5% Pure Retinol Night.) Use that twice a week and build up tolerance until you can use it every night. Then you can graduate to a cosmeceutical strength (just below prescription strength), says Fusco, following the same routine. (Fusco recommends SkinMedica Retinol Complex.) If your skin tolerates that, you can move on to a prescription retinoid (such as ReFissa or a generic tretinoin).

What goes on first? Apply products according to their consistency, beginning with the thinnest. In the morning, start with the treatment serum, then follow it with a lotion or a cream moisturizer. For combination or oily skin, begin with a vitamin C serum (try Perricone MD Vitamin C Ester Serum). Over that, layer a moisturizing lotion or gel (we like Neutrogena Hydro Boost Water Gel with SPF 15). For mature or very dry skin, start with a vitamin C or hyaluronic acid serum (such as Vichy Aqualia Thermal Dynamic Hydration Power Serum) and follow it with a lotion or cream containing glycerin. You can seal in the moisture by patting a face oil over that, says Fusco.(Clinique Smart Treatment Oil is a good one.)

Here's Looking at Me! 8 is the average number of times a day a woman checks her reflection, according to a survey by Simple Skincare.

Step No. 3: Protect
Did you know that 90 percent of the visible signs of aging—hyperpigmentation, wrinkles, sagging skin, broken blood vessels—are caused by ultraviolet exposure? That's why you'll want to apply an SPF 30 sunscreen every day, rain or shine. Look for "broad spectrum" on the label (to ensure it blocks both UVA and UVB rays). Chemical sunscreens (avobenzone, oxybenzone) have a thinner consistency and should be applied after cleansing in your morning routine so they can be absorbed. (We like L'Oréal Paris Age Perfect Hydra-Nutrition Facial Oil SPF 30.) Physical sunscreens (zinc oxide, titanium dioxide) are less potentially irritating than chemical sunscreens and should be applied last. (Aveda Daily Light Guard Defense Fluid SPF 30 is a good one.)