It’s not difficult to come up with an elegant, party-ready look. Here, celebrity stylist Mark Townsend simplifies this season’s prettiest styles. 1 of 6 Barbara Donninelli Roll-Up To create this look, use a Sarah Potempa Half-Up ($9, ulta.com), a three-inch-long piece of flexible foam with a slit in the middle. Slide hair, an inch from the ends,...