OK, so I'm no ladies man, in fact it's only recently that Iv'e decided to make some major changes in life after being in a spectacularly hilarious friedzone that ended in disaster, and an unholy amount of self-disgust at what I had become. The friendzone story is boring, irrelevant and embarrassing, so I won't go into it.

So last year, for the first time, ever (I'm 25... I know) I approached and chatted up a complete stranger. I'd never done it before. Like... ever. She was standing drawing something, and I realised she was engaged in a hobby we share (art). So, I did something completely alien to me. I asked her about what she was doing, told her that I had some training in it (I do), and that her art was very impressive (it was). To my absolute shock, she was only to happy to talk about herself and in turn ask about me. Had I just mumbled something about her skill and made my excuses to leave, I might be in a very different place today. Now... I messed it up at the end. It was time to leave and instead of asking for a number, facebook ANYTHING, I pussied out, said my goodbyes and left, never to see her again. I immediately regretted it (though in my defense, my even more beta friend was there and he just stood beside me, staring at me like the fucking undead - BO and all), as she was both pretty and fun to talk to - two qualities in women that while not rare, do not inhabit many of the women that I've known well over the years.
Something similar happened again last week (this time using my friend's work to talk to her - I first gave him an opening, but he just sort of said nothing and stared away, so I kept going), only this time I only really fucked it up after about 15 mins by being too drunk.

OK, the point I'm trying to make is that I used my knowledge of art and circumstance/location to have a conversation topic that I was actually knowledgeable about AND they had an interest in, and don't get me wrong, it made me realise that the dating world may not seem so hard after all... but this is about as far as I've gotten in so far as approaching women and I'm sure you can see how limiting this particular way of approaching women is.

So what I really need to know is, what are some great places to chat up women, how do I better learn to use my surroundings and more importantly, what else should I be looking for in the handful of seconds before approaching? Those almost-successes made me realise that if I'm to have a chance with any woman, I need to, well essentially spot a weakness to exploit.
I guess the obvious answer is to become an authority on as much cool shit as possible, but I'm wondering if those out there that rank themselves as masters at chatting up strangers might be able to offer any advice.

Edit: Jesus, I didn't mean for it to be so tl;dr, and I cut it down.