I'm not good at reading signal also.
Usually it's easier for me to read signals from words that they say. Like a girl will say things like she is free on which day, probably suggesting u ask her out, or say about what she like or don't like, maybe suggesting that what u should do to get her :))
Anw, I'm totally sucks (_ _ #)
But I know from my friends that when girls r talking to a man that she like, they have perplexed moment when that guy look into their eyes. Try to look into a girls' eyes for a couple of second and see her reaction, it might work.