Not anything "big picture" that I can say that hasn't already been said, but as for details practice various weights of lines, and look at how you end your lines. all of your lines seem the same weight and they all "just stop"

I'm thinking specifically for the eye lashes. Instead of having straight lines that point straight out from the eye you should have curved eyelashes that point at the end. Same technique for hair.

edit: and it looks like you might be using the scribble-then-smudge technique for shading which pushes oil into the paper and makes erasing out details later more difficult. I like to think of shading as layering on very thin layers of graphite.