I myself got confused, but i think there's some signs that she
treats u as a friend, or something more.
1) A friend, no matter how good, will not sms u almost every day,
be it to ask about homework, or talk about life in general.
2)She calls or sms to ask u about homework or ask for advice about
something, but then do not hang up or stop after getting an answer.
Instead, she drags on the conversation.
3)She will somehow appear in ur area of sight(i.e walk ard ur
cubicle in work, or walk near your seat) more often than
necessary.
4)She talks to u very excitedly, very chatty and seems at ease when
you are alone with her, but somehow, she clamps up, and talks very
little when in a grp.
These are some points which I encountered recently, and I don't
think it applies to EVERY gal out there. Hope it helps