I want to know what you mean by a "slut"....
IMO...a chick that has sex when she wants with who she wants is NOT a slut as long as she doesn't hide behind it. I've known chicks that try to play the "good girl" image when they have been with tons of guys. I consider them to be sluts. But I've also known chicks that have slept with tons of guys and don't deny it. They don't exploit their sex life...but they dont fake it either. I can respect women like that and don't feel like they are any different than an "active man".
I honestly don't think there is any correlation between looks and sluttiness...an ugly, plain jane type can get as much ass as a typical slutty looking chick. now...what is different between the two is the type of guys they are getting.
As for bringing looks into the picture...I can be mom, wife, girl next door looking one day and slutty black dress, cleavage, and stelletos another. A little makeup and hairspray can work wonders!!