I think you would enjoy drawing with a graphics tablet, that way you could make your line art look even better. Don't use a different line width for the face, though.
anyway i had totally forgot how it works so.. ^^''
anyway.. i wonder.. what kind of brush/pencil/pen/etc. do you use for make your line? or is the use of the tablet that make them so peculiar? :3
Like I said, I bought my (postcard-size Wacom) tablet to become better at oekaki. Tablets are not so expensive anymore either. Though not everyone seems to like using theirs (Catie, Rosamond).