It was kinda a self taught style, but I'll help where I can! (Posted the process as a spoiler to avoid annoying everyone who has to scroll through it)
[Rambling process.](/s Start off with big bold shapes. Circle head, angular jawline, circle for nose and triangle for lips. That sorta thing. You're only gonna bog yourself down with too many details too early in the piece. I personally establish my shapes, then add some more basic sketchy lines to give me a general idea of where my final linework will end up.
After that, I ink the thick lines, and the face really starts to come together. It's not until now that I even bother starting with any details.
After the lines are established, detail time! I try to keep my detailing fairly simple; (as you can see around the eyes) I try to avoid drawing every line I see, and instead opt to generalise them so a single line or two. It keeps it simple and still gives a similar effect, imo.
As for the final crosshatching/shading, it's a little hard to explain as I feel I have a pretty odd way of deciding where the shading goes. On a seperate layer below everything else, I get a bright colour/thick brush, and really try to block in where the shadows are (again, avoiding getting too specific with the small shadows and separating it into blocks). On a seperate layer AGAIN, I use a thin brush (thinner than any used previously), choose a direction for the crosshatching to flow, and start crosshatching ONLY where I had previously blocked in with the bright colour. After that it's just a matter of deleting your bright blocked in layer and you got yourself a picture!
Very last step includes telling yourself that it doesn't need a background despite knowing deep down it does. ._.)
Happy to post some progress pictures of the steps described after I finish work in 6-8 hours, if you'd like!