meh, sharp highlights occur where the surface reflects directly into the lightsource, so since there doesnt seem to be any real light source in the pic (aside from a general ambient).....no highlight. it always bugged me when people placed those jsut because that's how they've been taught ^^
I would say to avoid stuff this size when you are getting in to pixel art (and well after that i would still avoid stuff like this - its just not condusive). Same as everyone esle that jumps the gun, you really need work on your base drawing skills and tight pixelling skills, exploring the techniques that make both worth looking it. As far as the specifics go, i would say study anatomy (particularly of the face but if you are to have other characters than a general refresher would be in your best interest), work on value regions (jsut because everything is in shadow doesnt mean you can't have better lighting) and the relationship between pixels (hard lines are fine, but not when they get jagged - every percieved line should reinforce the forms)
I would say, if you are doing a scene, try something about GBA sized or smaller to begin with, and really make full use of a palette instead of adding a bunch of shades that you aren't using to smooth anything.
does anyone know of like, a pixel-dictionary where the basics of AA, dither, etc get covered? If not, perhaps make that a community project?