Well if your asking a shallow guy he'll give you the same answer almost any will. Boobs, butt, legs, etc. Not those aren't great, but there's more. At least I look for more. Pretty eyes, hair, skin, smile. But personality is big too, for me anyway. Someone that's sweet and happy, with an almost innocent appearance, but still knows how to be naughty.
would add to many of the answers...keeps good hygeine inside their body and out. not stuck on themselves, knows how to laugh, doesn't look like a prostitute but knows how to look attractive in clothes that fit them. example: an overweight girl in spandex 2 sizes too small.