"You need to decide what you want your curls to look like first," Desir told POPSUGAR, adding a rule of thumb: "If you take small sections of hair, you'll get tighter waves, and if you take thicker sections, then your waves will be looser."
Since Emily's waves are on the tighter end of the spectrum, go for smaller sections to mimic her look, and spritz each section with Bumble and Bumble Bb. Heat Shield Thermal Protection Mist (£25) or a similar product before going to work with your curling iron or wand. He used GHD's Soft Curl 1 1/4-Inch Curling Iron (£129) on set to achieve Emily's signature season two hairstyle.
A few pro tips from Desir: Start curling at the back of the head with your iron held horizontally for "more defined waves," then position the tool vertically once you reach the sides and front. Also, twirl each section of hair before wrapping it around the iron's barrel so it comes out more wavy than curly. Yes, it's an added step, but it makes all the difference.