When flirting with a complete stranger, what I'd most often do is smile.
I have a certain smile, which, is reserved for special occasions and I often use it when driving and a guy has let me out of a side road or something like that. It's a smile that's just a little bit broader than is strictly necessary and is accompanied by eye contact that lasts slightly longer than is comfortable.
If I get talking to the guy in question, I will flirt by being slightly more risque in my conversation than I would normally be. If I'm talking about sex or making naughty jokes, then the chances are I'm interested in you. Of course if I don't get a suitable response back, then I'll assume I'm making an arse of myself and stop!
The secret of flirting is that it's a TWO way thing. There are some people who are impossible to flirt with and some people who it's impossible NOT to flirt with! If you start off small, you can gauge the response you get and if your flirting is reciprocated you can move onwards to bigger more obvious gestures such as little touches (to places such as arms and shoulders - nowhere to 'dangerous' at first, to avoid being slapped!)
As for where to meet a suitable partner............
Now that IS the question....... and hell I'm not the person to ask. I met my b/f just a couple of months ago on Pixies!!!!!!! But I don't think that's the norm for this place.
