Put the lotion on 15 to 30 minutes before going outdoors. This gives the sunscreen enough time to be absorbed into your skin and offer you ultimate protection.
Squeeze out an ounce and a half the amount to fill an average shot glass. "Coat your body in a thin, even layer; there's no need to frost yourself like a cupcake," explains Noah S. Heftler, MD, clinical instructor in dermatology at Weill Medical College.
Apply it all over. Put the sunscreen on while you're completely naked so you can apply it everywhere. Then, when your swimsuit moves around, the skin that gets exposed is still protected. Make sure your legs and upper back are covered; melanoma most often strikes these body areas in women.
Be gentle to your face. It's fine to use the same product you use for your body, but if your face is prone to breakouts, invest in a sunscreen specially formulated to prevent blemishes.
Reapply every two hours if you are lazing around outside and every 30 minutes if you're doing something active that's causing you to sweat, even if the label says it's waterproof.