You came to a part which I'd like to talk about, which is the eyes
Eyes are the gate to the anime character's soul; the first thing most people do when looking to an anime(mostly the pictures) is to make eye contact w\the character
For the eyes,I agree that eye color sure gives effect, anyway, female eyes should be wider than male's eyes so it can give her the feminine sort of thing, & for the male: styled eyes surely gives him a strong-cool-attractive look