Prepare a template.
Draw the hair.
Add the main color of the hair and the dark shading.
Do the same thing to the top of the hair and add highlights.
Add accessories and finish any last details or blending. :D Then walah! Ur done! (And yes I know it is voila, the term for "there it is" in French.. But "walah" is funner to say xD.
I hope this was useful.. '-'
Sorry about my weirdness, I am just really tired right now and tomorrow I have an algebra test u.u... So goodnight/good morning/good day or whatever it is for you! :D