Do use a nude lip pencil. "If you want your color to last, you need to line your lips," says Chantelle Martineau, a Minneapolis-based makeup artist. Choose a liner shade that matches your natural lip tone. Line and fill in your lips, then top with a sheer lipstick or gloss. If you're prone to feathering (those wisps of lip color that leak into lines around the mouth), pencil will help prevent it.
Do prep your lips. Glosses may look slick, but they don't provide much needed moisture to the lips (which, unlike the skin, have few oil glands and can get chapped, even in summer). An emollient balm, like Carmex, underneath will do the trick. The balm will also help the color go on more smoothly.
Don't be afraid to layer. Like a light camisole under a tissue-weight T-shirt, sheer lip colors are made to be worn together. "Try a shimmer gloss over a creamy sheer lipstick, or mix two shades of sheer together," says Davida Simon, owner of the Makeup Room, a cosmetics studio in Denver.
Don't get stuck in a color rut. Sheer shades are ideal for experimentation. Even if you're not comfortable with bold lipstick, a bright but sheer lip color is an easy risk to take. "It's a way to test out the trend without being too trendy," says Michael Moore, owner of Simply Moore, a makeup consultancy in Denver.
Do go for the gold. A gloss with a hint of the precious metal's shimmer can soften any lipstick. "Apply it on top of a lipstick you think is too dark or the wrong hue and it will save it," says Bret Miedel, a Miami-based makeup artist.
Do toss old gloss. Some lip glosses are naturally stickier than others, but in time they'll all make your lips feel as if they're lined with flypaper. "The longer they sit, the tackier they get," says Martineau. Toss all lip color after two or three years.