Key rules every woman - fair, dark, freckly, young or old - should follow.

1. Look for Skin Changes: Do a mini skin check, ideally once a month, says New York City dermatologist Ellen Marmur, MD. Take three or four minutes to stand in front of the mirror naked and look at yourself head to toe.

2. Wear Sunscreen Every Day, Not Just on Beach Days: To avoid sunspots, premature wrinkles and cancer, swipe sunscreen on any skin that's not covered up by clots, says dermatologist Hema Sundaram, MD. 'Women of every complexion should use SPF 30 or above with both UVA and UVB protection," she says.

3. Watch your Shadow: Anytime you're outside, check your shadow perioudically. If its short, that means the sun is most intense and damaging. That's when you should cover up, reapply sunblock or find some shade.

4. Reapply, Reapply, Reapply: In a dermatologists dream world, young women would never spand more than a couple of hours poolside. But that's not how the average young woman lives, admits Dr. Sundaram. So for long days in the sun, reapply at least every two hours - more often if you're wet. (Did you know water-resistant formulas often last up to only 40 minutes?) "Reapply whenever you feel sweaty too. Sweat can wash away protection," says Dr. Marmur. Use SPF 30 to 50, and put on so much sunscreenthat it's like you're icing yourself like a cake, and rub it in. If you don'tm you're pretty much cutting the protection in half, so your SPF 20 is really only SPF 10."

5. And Never, Ever Use a Tanning Bed: If you're among the 44% of readers who have fake-baked in the past year, our experts want to grab you by the shoulders, give you a shake and yell, "STOP!!!!!" Using the beds at least once before age 30 may increase a woman's risk of melanoma by 75percent.

Found in Glamour.com May 2010