What do guys find attractive in women?

I honestly don't know what "sexy" or "hot" means. Guys thing my friend, who I think is very beautiful, is ugly but that she has a good body. Then there's this other girl, let's call her Danielle, who's wayyy too skinny and isn't very attractive and she's a *****, but guys are in love with her! It just doesn't make any sense! What makes guys attracted to a girl?