Well, vampires tend to have big, manga-like eyes. Angel eyes are more hazy, and the eyelids are curved down. Like a quarter circle. Eyelashes are more defined, as well.
Demons tend to have eyes that are like squished circles. Think japanese, only the eyelids are further apart to show more of the eye. This gives them a no-soul feel.
Human eyes vary, because there are different cultures mashed together. Practically anything goes.
Eyecolor wise, vampires eyes tend to be onyx, cranberry red, or gold.
Angel eyes are blue, light brown, violet, or pink.
Demon eyes vary, but most are shades of greens, browns, greys, navy...Flecks of yellow, white, or red are signs of other genes. Say, your great-grandmother was an angel. Then you'll have flecks of a different color in your eyes.
Humans can go crazy, but the most common colors are brown and blue.