Just a quick tutorial for =alexrashid
on shading hair. c: Kinda sloppy because I wanted to get this to them as soon as possible (and I'm not used to GIMP at ALL, which made this a little awkward to make XD), but the general steps are there. C: After you get the idea of it, it's all about playing around and looking at references to see how hair reacts to different lighting, seeing what different brushes you can use to get your desired effect.
If you have any questions, please feel free to ask!