I just dont see him as the boyfriend type, Question Gals Options

[AngryBaby]

my friend Zach in one of my classes likes my other friend Ashley. Zachs was cool with her and all, gets to know her, they become friends and even start flirting.(at least i thought so) later in the year Zach finally gets the strength up to ask her out. But when he asks her out, she rejects him! she gave the lets be just friends thing. so they're still just friends now. I asked Ash' why'd she rejected him. She's all like "I cant really see him as the Boyfriend type ya know? i can only see him as a friend, and thats about as far as its gonna go."
So i just said "oh, i get what you mean" i kinda do, but a few questions.

The questions are
what did the person do wrong that he would be only considered as a friend?
What is the difference between the guy that would be the Bf and the bff, that the Bf would get the girl over the person who knows her better, and they have a better time with ?(lol did that make sense?)
those were Zachs' questions heres my question

If i were to meet a girl right now for the first time and i started liking her, what would be the things i would do that would lead me down the path of "lets just be friends" oppossed to the boyfriend path. and what would be the the things i would do to get to the path of Boyfriend opossed to just friend.
because if it were me id want the best of both worlds a Gf and a bff.

Oh god im done i hope that made sense, cuz my damn fingers hurt now.
i would type more but i wouldnt do that to ya.

[xoxvietbabyy]

Maybe she's got her eye on someone else, or maybe she just sees him as friend? Many possibilities.