How do I make a girl like me?

I've recently had a crush on a girl and I have tried getting closer to her. So far it's going well and we chat on a fairly consistent basis.

However, I believe that she only sees me as a friend.

I would like to confess my feelings to her, but she isn't prepared to commit herself to a relationship yet, therefore a straight out confession would probably end up in disaster.

I'm hoping to go with something far more subtle, like getting her to like me back as more than a friend or hinting to her that I'm interested in her, however I do not know how to go about doing this.

I want to do something about it while I can, before we become too close which would make it all the more difficult for me.

So how could I develop this relationship towards a romantic direction?

Also, I would like to know how to tell if she likes me as merely a friend or as something more, like perhaps little signs to look out for.

Thank you!