I think the flat shading style is wonderful; if you want to add more volume to the hair you could add a few lines to define the direction and shape a little more.
those edits are great and gave me some ideas
, I think I'll put different styles to choose from (with lines and/or without).
Also grab update. ~
Some more progress.
I'vent got the hair lines look as I'm aiming to, so characters still have their original hairs.