I think that cold looks are because women are afraid. They are afraid that you do something awkward that makes them look bad or something else. I would ignore their fear and approach them anyways.
If you hesitate even a bit, that makes them feel even more insecure and fearful. They want to feel appreciated and if you approach them, look them into eyes and smile, they feel it. Women need validation much more than men.
If they are not approached right away, they might think that they need to fix their make up etc. Man needs to be spontaneous and fluent.
There is more into it though. Sometimes they give you cold looks, because you are cold. If you smiled a little bit more and had more fun, they might give you approach invitation and not be afraid. But yeah, staring is not good.
Eye contact with smile, is not awkward. You can signal, that you have noticed the girl, but you are having so good time, that you don't feel the need to approach. Then approach later if you have time. You have priorities in life after all
