eyeglasses on model FACIAL GEOMETRY

Your shape is an inverted triangle, with more weight on top: Artist Maria Taylor, 29, has a broad forehead and cheekbones tapering to a narrow chin. (Don't worry if your face doesn't fit exactly into our categories—lots of us are hybrids. Just decide if you're essentially angular or curvilinear, then try on glasses in a contrasting shape.)

eyeglasses on model THE "BEFORE PAIR"

The straight-across look of these boxy black rectangles accentuates the width of Maria's cheeks instead of minimizing it, Lochli-McGrath says. They're also sitting way too low on her face: Always check that your eyes are centered in the frames when you're trying on a pair (and the temples, or earpieces, should be level, not tipped up or down).

eyeglasses on model THE "AFTER" PAIR

One way to lighten up the wider portions of a heart-shaped face is to wear airy, rimless glasses (Robert Marc, "368," $425). Butterfly lenses, which are slightly wider at the bottom, give a pointed chin more of a buildup. "It's amazing the difference you feel in your energy and confidence when you have a great pair of glasses," Maria says. If you're on the computer a lot, Lochli-McGrath recommends lenses with an antireflective coating that eliminates glare and reduces eye stress.

eyeglasses on model THE RIGHT SUNGLASSES

Softly curved wraparounds (Via Spiga, "VS 411-S," $160) hug Maria's face and tone down the angles. "I like big, jazzy, extravagant sunglasses," she admits. "No subtlety! These have a shininess to them, a bit of bling, and that's my style." The glasses most likely to succeed will probably have the same basic palette—warm or cool—as your skin, hair, and eyes (see how bronze illuminates Maria's complexion). But if you try a few that break the color rule, you won't get arrested.