Just the body shape, in general. Especially if she's very toned or thin. I'm petite but when I find women who are more petite than I am I find them incredibly attractive and cute (or sexy if that's more their "style").
Sometimes I get upset that I support what can be a very unnatural and unhealthy body image, but it's the natural ladies that I'm attracted to.
Eyes? Lips? A little lower perhaps? What do you find most ascetically appealing about your own sex? Weather you are a lesbian/bi/pan/other or not.
I love angles on a man, so it is only logical that I love a woman's curves. I love the curves on the breasts, waist, butt, hips, hamstrings you name it!
I love women's lips, but also the fact that they're less hairy than men and more likely to groom themselves more. I hate stubble. I hate, hate, hate stubble. ^^U