I personally think, and finally learned a long time ago that I had to be far more truthful with women. I would rather get rejected outright than suffer through the maybe/maybe not in my mind and longing from afar. Women are sensitive, and will normally let you down easily and politely, and stay friends, cause they think that men and women can be friends without a sexual tone. When a woman thinks your not interested in them that way, they turn off their own feelings rather easily.

You don't need to ask them to fuck, but ask them for coffee or a drink and see what they say. They prefer a smooth and slower approach anyway until there is mutual interest. But once the conversation is one on one, don't spend hours trying to be a friend. Make it obvious. Touch their hand, walk up behind with their drink and touch their shoulder so they turn around, see how they react to the light contact.