I was recently looking through some of my older sketchbook pictures that I drew several years ago, when I first began getting acquainted with doll making. Here is one of my favorites.
It's just a simple eye that I did in pencil, then duplicated it and colored it in with colord pencil. I love the simplicity of it, showing how a little bit of color and shading makes such a difference. You can photocopy the sketch and print it out onto paper, and try practicing. Eyes are so much fun to draw, and they bring a doll's face to life.