The key is to avoid being in the sun or using sunlamps. If you're going to be in the sun for any length of time, wear clothes made from tight-woven cloth so the sun's rays can't get through to your skin, and stay in the shade when you can. Wear a wide-brimmed hat to protect your face, neck and ears.
Remember that clouds and water won't protect you--60% to 80% of the sun's rays can get through clouds and can reach swimmers at least one foot below the surface of the water. The sun's rays can also reflect off of water, snow and white sand.
Tips on preventing skin cancer :