If you make a woman laugh, your attractiveness increases quite substantially.
I find this to be 100% accurate. as soon as you have a woman laughing, the whole game changes, you are both more relaxed and you can just be yourselves. If you can keep that good vibe going for a while, then you can slip in a very mild sexual innuendo and how that is received. If she is receptive, keep it light and humorous for a while longer and then hit her with another one.
Let her know that you are a sexually viable entity,but very subtly. if she acknowledges that, she is in tune with what you are doing, and probably thinks you are attractive to her in that way. If she shuts the door decisively on any playful banter in that dept., you are more than likely wasting your time.