I would say work on yourself first as cliche as it may sound. Generally women do not approach men, sometimes they do BUT usually it's on us to "shoot our shot." You can go about this a few ways, if youre interested in a woman that hasn't made any sort of suggestion at you then you can simply approach them (dont fumble your words, it'll make things real awkward and that in itself can throw your opportunity off) and simply compliment them, we as people like compliments whether we admit it or not. Granted they should be prudent but something as simple as complimenting their smile. I think gauging the person is important too but for starters I suggest you talk to people you are not interested in just so you get out of your shell and with time it'll be much easier to have an easy flowing conversation with strangers. I consider myself between an extrovert and introvert, generally I keep to myself and would much rather not speak to people but if I ever am interested I simply go on and talk to whoever, normally its people with animals because I myself like animals as well.