Rule-breakers, this one's for you. Famous fashionistas are flaunting horizontal stripes without looking, well, wider. What's the story? Wearing variegated stripes (as opposed to lines of the same width) can actually highlight your favorite features. "The black and white contrast with the silky textile keep the eye moving without looking flat," says designer Ara Kim of Plastic Island. "We wanted something vibrant and easy for the daytime, but dressy enough for going out."

BUY ONLINE NOW
Mandy Moore's Plastic Island dress, $129; at shopharmonylane.com.

—Betony Toht