Good work, I like them!
Two ideas regarding the blurry hair:
1. There should be an option for your paint tool that's called "hardness". Set it to 100% to avoid blurry edges. But if the picture is very small this might not be enough.
2. A trick I use for more accuracy is to enlarge the picture by at least 200% (not just zooming - change the actual size of the picture). Usually it's easier then to work with the paint tools and they become less blurry. Of course everything else gets a bit blurry, but that's not important because you will change the size back after you are finished.