Basic standards. Certain facial types and shapes are generaly found more pleasing than others. Symmetry for instance. While many people think that people's faces are symmetrical(one half of the face matching another), this is generally not true. The more symmetrical the face the better.
Women's chins are narrower and pointier. Elfin looking. Men on the other-hand, have wider and rounder chins. Strictly from a physical stantpoint, a woman with a wide chin doesn't look as good as one with a narrow chin. Men with narrow chins tend to look too bishonen.
THis also applies to body types. For women, optimally, a 3-2-3, breast, waist, hip ratio is best.
Of course, bear in mind, this only applies to physical beauty. There are other mental, emotional, and spiritual factors which are far more important.