When it comes to styling your hair, curling irons are an incredibly versatile tool  — you can use them to create beachy, undone waves for a low-key day look, voluminous barrel curls for a bombshell effect, glam finger waves for a formal evening affair and countless other styles. But as useful as the curling iron may be, it’s not particularly easy to use, especially if you’re not frequently brushing up on your skills. To help you figure out how to curl your hair, make the curls last and be happy with the finished product, we turned to Sarah Potempa, celebrity hairstylist and founder of The Beachwaver Co. Keep reading for her tips on how to curl short, long and medium-length hair.