I'll not give any sure-fire signs of attraction or interest, but an above post basically said it all about how she will test you and your responses. Men do it too and it's totally an instinctive thing, in fact I've been with a few who test continually on a day to day basis. It appears to be a matter of insecurity... Makes me laugh a little, really. ^ . ^
Be mindful of keeping calm, cool & collective. I know that sounds tacky but it's important not to appear to insistant or obsessive. & Yet you must somehow find a way to receive her emotional output while keeping a balance of receptivity, and actually staying true to who you are. Someone mentioned "Act as if they're all interested" Yes!! This is key -- Regardless of what type of person you may be or who you're looking for, believe you will have the one you fancy most. Confidence (*ahem* in moderation, boys) is always highly attractive as well as it is respectable. = )