By now, everyone should know how dangerous it is to expose your skin to too much sun. The risks associated with overexposure have been well publicized, and people are taking more precautions, including using sunscreens with higher sun protection factors (SPF).

Then why are melanoma rates still rising?

"We think mismarketing of sunscreen really contributes to that problem by giving consumers the idea that they can rely on sunscreen and be out all day safely in the sun," said Sonya Lunder, senior analyst at the Environmental Working Group. "People misuse sunscreen and get more sunburns, not fewer."

Melanoma is one of the deadliest forms of skin cancer. To that end, the government has tried to make it easier for consumers to decipher sunscreen labeling.

In 2012, the Food and Drug Administration rolled out new rules defining the term "broad spectrum," which means a sunscreen offers protection from both ultraviolet A (UVA) and ultraviolet B (UVB) in proportional amounts. Before, sunscreens did not address UVA radiation, which causes skin cancer and early aging but not necessarily the telltale signs of sunburn.

Additionally, claims such as "waterproof," "sweatproof" or "sunblock" are no longer allowed.

Nonetheless, dermatologists say there's still a lot of sunscreen misuse.

The biggest problem is that most people don't use enough.

"Nobody uses enough — ever, ever, ever," said Dr. Jason Reichenberg, vice chair at the University of Texas Southwestern at Austin department of dermatology. "You're supposed to use one ounce — which is as much as a shot glass— to cover all of your exposed body areas.

Apply it at least 15 minutes before going out, and that amount needs to be reapplied every two hours — more often if you're sweating or swimming, he said.

Wear sunscreen on a cloudy day, too. "You can still get a bad sunburn on a cloudy day as the ultraviolet rays still pass through," said Dr. Elizabeth Martin, a dermatologist with Pure Dermatology & Aesthetics, in Hoover, Ala.

Being "sun smart" is just as important as sunscreen use, Martin and Reichenberg said. That includes trying to avoid the sun between 10 a.m. and 2 p.m., wearing a wide-brimmed hat, sunglasses and preferably long pants and long-sleeved shirts, they said.

The tanning booth myth

Forgoing sunscreen to get vitamin D exposure from the sun is a bad idea, the dermatologists stressed. Instead, take a supplement or eat foods rich in vitamin D like fatty fish, or drink fortified orange juice.

And never go to a tanning booth. "It's a myth to get a 'base tan,' " Martin said. "All you do is damage the skin."

For over-the-counter sunscreens, the dermatologists recommend buying a broad spectrum with an SPF of at least 30. Mineral-based sunscreens, those with zinc oxide and/or titanium dioxide, offer the best coverage.

For chemical-based sunscreens, a key ingredient is avobenzone, which is one of the best UV filters. However, Lunder said, it breaks down quickly, which is why sunscreen needs to be reapplied.

Some over-the-counter brands the dermatologists recommend are Aveeno, CeraVe, Cetaphil and Neutrogena. The Environmental Working Group's website has a searchable database based on different types of sunscreens.

Although spray sunscreens are popular with parents, the experts frown on these because it's difficult to tell if the sunscreen was properly applied, not to mention the chance of inhaling the spray. In fact, the FDA is investigating the potential risks — especially for children — of inhaling spray-on sunscreens. Because of that, Consumer Reports recommends those products "not be used by or on children."