Glamour contributing editor Theodore Leaf breaks it down: Starting with towel-dried hair (don't comb; just detangle with your fingers), spritz a wave spray like Sally Hershberger Mineral Spray ($24, sallyhershberger.com
) from roots to ends. After air-drying or blow-drying with a diffuser, wrap random pieces around a 1 1/2-inch curling iron, winding away from the face. Rub a bit of pomade between palms, then "squeeze the ends of your hair to define," he says. If your hair is fine, spray dry shampoo from mid-shaft to the ends "to make it more mermaid-y" once you're done. And if you're naturally curly, briskly run a flatiron from the middle to the ends of dry hair to stretch out curls, mist with texture spray, and use pomade to separate the tips.