BOX: How to play it safe Scientists say the best way to prevent skin cancer is to minimize the risks. Their advice: Avoid the summer sun altogether at peak hours - between 10 a.m. and 3 p.m. - when rays are strongest. Water and cloud cover reflect sunlight, so if you're out on the water or playing outside on a cloudy day, take extra care. Avoid ''tanning booths'' and artificial suntan devices that add to the cancer risk and make skin wrinkle and age. Cover up. Wear loose-fitting, light-colored, long-sleeved shirts and long pants. Wide-brimmed hats also help to shield you. Wear protective clothing, such as hats and sunscreen with a sun- protection factor of at least 15 whenever outside, not just at the beach. This is especially important for young children. Use a stronger sunscreen - with a sun-protection factor of at least 20 - if you have freckles. Children who get freckles after being in the sun face a greater risk than other youngsters of developing skin cancer. Know your skin type. If you have freckles, blond or red hair, or blue eyes, you are more sensitive to the effects of the sun.