The easiest new shape for evening is a slouchy T-shirt dress. Joy Bryant donned a sequined Erin Fetherston dress for Glamour's Fashion Gives Back event. "My style is a blend of something romantic and ethereal, balanced with a girlish sensibility," the designer has said. "I like to approach sophistication in a joyful, playful way." The simple silhouette can be paired with towering heels after dark and dressed down with ballet flats during the day. A T and slippers—what could be more comfortable?

—Betony Toht