This hair tool right here. The Bed Head Hair Crimper
Section your hair (I leave about a third of my hair down to start with)
Use the crimper tool to crimp the roots in the bottom half of the hair, avoiding the pieces closest to the ears
Curl/style the layer you’re working on
Pull down a section of hair at ear level
Crimp the roots on the section, avoiding the pieces closest to the ears
Repeat the steps up until the top layer of your hair. Do not crimp the top layer.