Summer is filled with fun outdoor activities, but these pastimes don't come without a cost to your little one's skin. In fact, it only takes one blistering childhood sunburn from unprotected sun exposure to possibly double the risk of melanoma later in life, according to The Skin Cancer Foundation.  While the sun is to blame for more than 90 percent of all skin cancers, the majority of us, young and old, don't use sun protection regularly - less than 33 percent. By following a few practical tips, and stressing the importance of proper skin care early on, you can help protect your children from the sun's damaging rays - not just during the year's warmest months, but year-round.

The eight tips are below from "Best Doctors in America" honoree Dr. JJ Levenstein, a California-based pediatrician, fellow of the American Academy of Pediatrics and co-founder of MD Moms (a pediatrician-created personal care line for babies).

1. Protect your child's skin early. For babies, if avoiding direct sun exposure isn't possible, The American Academy of Pediatrics (AAP) recommends protecting them with a broad-spectrum sunscreen that has at least SPF 15, and offers both UVA and UVB protection. UVA rays (the "aging rays") penetrate deep into the skin to cause wrinkling, spotting and skin cancer, while UVB (the "burning rays") sizzle the top layer of the skin, also increasing the risk of skin cancer. Remember that while sunscreen - if used correctly - can help protect against sunburns and certain skin cancers, it should not be used as a reason to stay in the sun longer.

2. Physical, not chemical. Because a young child's skin is sensitive, use a physical sunscreen that contains zinc oxide and titanium dioxide (pure physical block ingredients), as they offer the safest protection with the least potential for skin irritation. A physical sunscreen deflects, rather than absorbs, UV rays, and starts working the moment it's applied. By contrast, chemical blocks may be more irritating and may take up to 20 minutes to activate, increasing the risk of sunburn if not applied well before heading outside.

3. Use the right amount. As a rule of thumb, use one ounce of sunscreen (the size of a shot glass, or a palm full) per application (for an adolescent or adult, use 1.5 ounces). MD Moms' Baby Silk Babysafe Sunscreen Towelettes, for example, contain a pre-measured dose of SPF 30+ physical sunscreen to properly cover the average 2-year-old from head to toe. If using chemical sunscreen, apply it to your children's face and body, wait 20 minutes, and then reapply to catch any missed spots. Apply coverage twice to areas of the skin that wear against clothing or sweat. Test for reactions to any new topical product by first applying a tiny amount to a small area of skin on the extremities or torso. Wash it off and discontinue use if your child experiences redness, itching or irritation.

4. Apply regularly. When dry, reapply sunscreen every two to four hours.  If swimming or wet, however, use sunscreen at one- to two-hour intervals. Consistent sunscreen use is most important when around water, sand and snow. These reflect the sun's rays and increase the risk of sunburn.

5. Check the date. Follow expiration dates and dispose of sunscreen once the date has passed. Typically, if your sunscreen is more than two seasons old, it has lost its potency. Still, if the date is in question or not listed, call the company or purchase a new bottle.

6. Seek shade. Avoid direct sun exposure from 10 a.m. to 4 p.m. The most damaging UV radiation occurs during these peak hours of the day. If outdoors, find a shady area for your children to play in, in addition to properly applying sunscreen, during this time.

7. Dress for the sun. Don your child in clothes with UV protection (Cabana Life and Wallaro Hat Company are examples). Alternatively, an SPF rinse on tightly woven cotton clothing can raise the SPF value from 5 (the SPF value of an average T-shirt) to SPF 30. Shade your child's face and ears with a wide-brimmed (2 1/2 inches) hat. Further, protect their eyes with sunglasses that block 99-100 percent of UV rays, and check for ANSI (American National Standards Institute)-rated UVA and UVB protection.

8. Lead by example. If your children see you walk the walk, they'll be more likely to understand the importance of sun protection. And remember: It's better late than never when it comes to protecting your skin, too.

By encouraging and practicing sun safety, you can help your children enjoy the summer sun the healthy way - and rest easy knowing you've taken the preventative measures to start protecting their skin for the long-term.