So, if you talked to her normally, which you should, but NEVER did anything flirtatious, how would she know that you're not looking to be just friends? I'm not saying don't talk to her, I'm just saying throwing in the occasional flirty comment is good to ensure that both she and yourself are reminded that you're looking for something more than being friends. If I'm wrong, will you please provide a counterexample?
Relationships are a sliding scale.
At one end you have enemies, at the other you have lovers, in the middle is neutral.
Part-way between neutral and lovers is 'friends'.
You can't get to 60 mph without first going 30mph, at least for a moment.
You can't get to be lovers (or anything else beyond 'just friends') without first being friends, at least for a moment.
You're not going to go from neutral to lovers in a heartbeat, and if you think that has happened, then you almost certainly do not know each well enough to be in a long or even medium-term romantic relationship with them.
If that is your goal, to be boyfriend/girlfriend with them, then you need to become friends first.
If you are just interested in a one-night stand, then you're still going around this the wrong way, because you aren't being forward enough, and you haven't even met her properly yet.
There is no such thing as the "friend zone". This is just a lie that people tell themselves when the person they have romantic affection for doesn't have romantic affection for them.
Becoming friends with a person in no way guarantees, or even implies, that you can't become romantically involved.
In fact, the opposite is true. Not becoming friends with a person, means you will almost certainly not get anywhere with her.
Even if you're giving her signs of your romantic affection, why would she be interested in you at all, if she doesn't know anything about you, or you don't know anything about her, and neither of you know if the other actually cares about you?
Do not trick yourself into believing in the "friend zone". You will come to resent every time a relationship you would have liked didn't form. And that will probably happen a lot, it does to most people. And you'll start thinking people owe you their affection, and that will change how you interact with people, and it will not make you liked.
The reason relationships don't take off can be for a couple of reasons. Because the other person does not have a romantic/loveual affection for you (which you can't simply create in another person), or because they generally don't like you or things you have said/done, or they're not even interested in such a relationship, or possibly are looking elsewhere (as they are allowed to do).
The reason your relationship didn't take off IS NOT because you got stuck in the "friend zone".
And Foxscotch is perfectly correct about the flirting.
It is not necessary for getting to a romantic relationship. It is not even a proper sign that you are interested in one.
There are lots and lots of people who flirt as part of their natural means of conversing with people, without an interest in others romantically or even loveually.
Your flirting is definitely going to mean nothing at all when you haven't even met her properly yet.
That's not to say don't flirt, but you cannot rely upon it to be the thing that lets her know you're interested in her.
