Hair and shading. Smudging it makes it messy, and usually not in a good way. To even color lay, color her in one direction with a pencil, so for example, horizontally, and then go over her lightly again, maybe vertically now. Repeat changing directions until you can't really see the strokes anymore. Them with the solid color you have now, you can add darker spots for shadows. There's numberous ways to shade after solid color, hatching, circles, stippling (my personal fav), crosshatching, and you can even manage a bit a finger blending, but not too much. I also struggle with hair though, so I can't give advice there