Try smiling directly at them, making direct eye contact and also try positioning your self alongside them, either watching for transit, in line, or seated at a coffee shop and you just make conversation on what you see, like a book they are reading, cologne they are wearing, phone they have, music they might be listening too or so isn't odd because it is right there in front of you to be discussing. If are polite, smiling friendly and kind about it no one should think weird you are addressing them, unless married and don't want the attention. If you like them, they are single and they seem to give a vibe of interest why not ask for their phone number or business card, in a big city like NY lots have business cards.
“Accept — then act. Whatever the present moment contains, accept it as if you had chosen it. Always work with it, not against it. Make it your friend and ally, not your enemy. This will miraculously transform your whole life.”
― Eckhart Tolle