To transform a daytime LBD, lose the cardigan and add some baubles. "Bigger is better for evening," says stylist George Kotsiopoulos. "And you can't go wrong with a bit of sparkle, especially if your starting point is a simple dress without much embellishment." Try a pair of colorful danglers or layers of gold chains ("you can get great faux ones at Forever 21") plus a gold cuff.
Swarovski-crystal earrings, Elizabeth Cole Jewelry, $373; elizabethcolejewelry.com