That is actually pretty good, though it's hard to say more without seeing the reference photo. :v
As for hair, it depends on the colour. If it's white, you hardly need more than vague outlines, while darker colours will obviously require a shit ton of pencil strokes. Just remember to make room for the highlights (which, due to individual hairs being cylindrical, are NOT like those of a shiny dome), and you should be good to go. I personally have more trouble stylizing hair than drawing it realistically.
I was... actually too embarrassed to post the photo because what I did looks nothing like her. So far, everything I've been doing is constructional drawing, so I was more focused on actually making it look like a person than copying the photo (which I know I need to do more of but the idea of copying something someone else has already done doesn't really interest me at all). I've been told hair is like most anything else, block out the midtones and work darker, then use a kneadable eraser to lift out highlights. There's also apparently some Proko videos on youtube I need to sit down and watch.
Here's the original.She has a much more aquiline nose and stronger jawline, longer face and blah blah. I've also been using pens so long I don't remember how to graphite at all, but I can only practice so many things at a time and pens are awesome. Still, it looks more or less like a human being, so I'm pretty pleased that this is my starting point to work up from.
Made another piece of pixel art, and also put it on RedBubble, too
http://www.redbubble.com/people/happyslapp/works/21132086-bricked-up-8-bit-heart-shirt
As mentioned in the happy thread, that's a really cool design! I like it when the art interacts with the canvas, if that makes sense. Also, speaking of Redbubble, I M ALSO MAEK SHIRT
so if you're frequently late then this is totally a thing for you
Curious, I've heard a ton of stories of stolen art that the cheapy T-shirt outlets just steal from places like etsy and the like. Would you be worried about stuff like that? Also if I may pry from both of you, do these actually sell in appreciable numbers? I'm kind of a plain shirt guy, but these kinda things seem popular.