Avoid streaky nail polish.
"The key to layering nail polishes — and nobody wants to hear this — is waiting in between coats,” said Deborah Lippmann backstage at Badgley Mischka, where she mixed two shades, Blue Orchid and La Vie En Rose ($17 each, deborahlippmann.com), on models’ nails. “Apply thinner coats. If you start putting too much on the first round it will never dry, it will streak forever." Your best bet? Wait two minutes in between coats.