My dermatologist was just telling me how frustrating it is trying to get her patients to use sunscreen properly.

We decided that with Memorial Day right around the corner, and the official kick off of summer right in front of us, it would be the perfect time to post a blog all about how to apply sunscreen.

First up, understanding the code.

UVA rays are the aging rays. They very busily and at very high speed break down the elastin and collagen in the skin, fast tracking your skin to wrinkles and sagging.
UVB rays are the burning rays.
Make sure you purchase broad spectrum sunscreen - that offers you protection against the twin demons of UVA and UVB. 

Facial SPF:

Use a free standing Facial SPF. If your moisturizer or foundation have SPF in them, just view that as a bonus. No one applies a sufficiently thick coating of moisturizer or foundation to give full protection via any SPF in the ingredients.
Use the highest SPF you can find. The labeling laws are about to change, so that the highest will read SPF50+. Until that time I still buy SPF 85 or 100. If there is a sliver of a chance that my face and throat are getting just a whisper more protection, I want it!
Try to find a "dry touch" formulation. I like Neutrogena Dry Touch with Helioplex facial SPF. It doesn't leave a film on the skin, and doesn't break me out. Plus makeup sits on top of it beautifully.

Apply at least the size of a quarter. You should have a white film on your skin that takes some rubbing in.
Allow it to penetrate the skin for a couple of minutes before putting any makeup on top.
Apply 30 minutes before going out into the sun.

Make sure you reapply sunscreen frequently throughout your day.
If you are wearing makeup, reapply a powder sunscreen over top, such as the ColoreScience powder sunscreen products.
(I use these on outdoor shoots all the time)

Sunscreen for your body.

There are many different formulations of sunscreen.
I recommend for your body to start with a traditional lotion form.

Use a full ounce ( a shot glass full) and apply thickly and liberally all over. Again, you need it so thick that you have a white film that needs rubbing in.
I recommend at least an SPF of 30. (my dermatologist does too!)
Sports formulas and waterproofs are great, but not always consistent, so always, always reapply, especially after swimming and towel drying.

Sprays are super convenient, but best used only to reapply. 

You will never get the thick, even coat that you do with a lotion, so always start with the more controlled product.
If you are going to be in the water, re-spray every hour, regardless of how "waterproof" the product is.

Don't forget the backs of your hands, tops of your feet and your ears.
Ideally wear a hat with a broad brim to protect your scalp, ears, face and neck. If you don't have a hat, be very aware of your scalp. Most people don't realize how prevalent melanoma is in the scalp, and it frequently goes undetected.