Women expect guys to hit on them at clubs, that's where they're at their most defensive.
Anywhere else is fine, on a bus, in an elevator, waiting in line, anywhere where you and they have reason to be and you're going to be there long enough to have a conversation.
You know how to make friends with other guys? Just do that.
Be happy, joke about something, then gauge her reaction, is she smiling too or avoiding eye contact? Don't take it personally if it seems she doesn't want to be bothered, just play the numbers game and you'll find a few that are friendly back, ask them about their day or something relevant to the situation, have lighthearted conversation for a while, tell them your name and ask for theirs, when the time comes to part ways say you enjoyed meeting them and ask for their number.
This will fail 95% of the time.
100% if you're not confident and relaxed, if you're not then you just need to hammer down your inhibitions until you are and how do you think you do that? Yep, by doing it.
I don't do this, this is what my extroverted father tells me to do.