Guys giving guys dating advice...I love how everyone says "don't be friends!"
Speaking from a female perspective (of course, this won't work with ALL girls), I prefer to be friends first, because then I can judge what taking the next step would be like. I really believe that the "I want to be friends" or "I don't want to ruin our friendship" excuses are absolutely rubbish.
To put it bluntly, if a girl says this, she's just not interested in a romantic relationship, whether that's because you're not her type, she doesn't find you attractive, whatever.
I don't know one girl who has gotten into a relationship with a guy who is a mere acquaintance, because a certain degree of trust usually needs to be established for a girl to commit.
If you're friends with a girl and you both like each other, it WILL happen. There won't be any of this "we're friends" rubbish, because the next logical step from a platonic friendship is a romantic relationship. Love usually comes from compatibility, so if you're friends, you're able to forge a deep connection from the off.
It's just like...how "the spark" is a term made up by guys so they can have sex with someone. It's all a charade!
OP: All that's happening is that you just haven't found a good enough girl yet.
I'm sorry if it upsets you or whatever, but "we're just friends" is a lame excuse so that she can duck out of having to say "not interested" and avoid hurting your feelings so that she doesn't look like the bad guy.
How much easier would it be if girls were forthright and honest? If I like or don't like someone (in general or romantically), they damn well know about it. I get so sick of mind games, and I think girls play them to their full effect. At least you know if a guy just wants sex. Women can play games to expand their own egos, out of resentment, out of pure malice...
Not saying only girls act this way, and only guys act that way, there are exceptions to every rule, so I don't mean to offend anyone who's not like this, I'm just generalising to make a point.