answer to a question in the patreon discord
so for this, i went with my favorite hair type to draw which is flowy and straight. a lot of this can still be applied to other hair types, its all about being consistent with a shape or movement. with curly hair though, it's also adding coils/spirals.
i start with shape. the silhouette (or lack thereof) of a hairstyle can be very, very telling of character. big hair is often associated with big personality, slick/thin hair close to the scalp can give a serpentine look, etc.
after shape is established, i section off the hair into vague parts that are basically shapes within shapes. this makes adding detail easier because you're kind of given a direction to make the flow line, etc.
throughout this process i touch up quite a bit, changing things to what looks better from a strand in the face to how much is over the neck. you want to know just what you want to be shown through the hair. after, i establish the depth of the hair with shadows and stuff. then when coloring i use those sections in the hair for things like ombre effects/highlights/etc.