damn people, be real
The guy has never talked to a woman in his life. I straddle the line of extroversion, probably just barely passing over it, and I can still psyche myself out on the "just walk up and say hi" routine. Because, let's face it, even for natural conversationalists that's gonna be tough, even if it doesn't bother you much to see the conversation fall off or take the polite rejection. Seriously. As nice and down to earth and helpful as that sounds, it's hard enough for well-socialized but quiet people to put that into practice. For someone like OP?
How is that realistic advice?
OP, this is what you need. You need to talk to women. That's it. Before I look like a hypocrite though, let me elaborate! See, you need to disengage the idea that women are some kind of deistic fourth dimensional creature that you don't understand and oh god they smell nice oh god why can't I talk oh man cold sweats. A girl is just a person, like you or me or the people in this thread giving advice that I would assume is dizzyingly incongruous for you.
She's not gonna bite you. Jambino and Falcon are right that you have to "just not worry about it", in a nutshell, but you really need to drill that in. Don't even think of her as a "girl". Think of her as a person. Just a person you're gonna talk to. Like anybody else (you talk to men, right? Surely? Probably without too much issue?)
But here's the big one. In training your ability to not give too many ****s, I think you should just erase the idea of trying to date a girl or ask her out or get her number or whatever. It's not that I don't think it'd help, but I think it'd put way too much pressure on you. The kind that's making you break out in a sweat at the idea of approaching.
Just chat a gal up sometime with absolutely no ulterior motive. There's nothing to be awkward about then, right? She's just a person, you're just a person, and you were nearby and she wasn't preoccupied with anything, so just struck up a conversation. No intentions. No big deal! Just have a conversation, separate, walk away, think about the conversation you had and learn from it for the next one
Do this a bunch. When it starts feeling less terrifying, maybe then you can start going for numbers, though I'd recommend making some friends just because you'll get socialized into, well, an adult social life. Trying to break in through dating is more pressure than you're up to I think
it's a long road, but I honestly think this is the best one you've got. Just talk about little nothings for a while, and again with no ulterior motive, then try easing into more substantive conversations, and so on
and yeah the hobby thing really can work, for reasons that have already been said. That's a great way to make some friends as well, since you'll know you at least have that in common
Ultimately this still does boil down to one of those "just do it" advisings, but that's what everything in big spooky social realm comes down to in the end. Posting on SWF isn't gonna help, at the end of the day. All the academic study of social life you can handle isn't going to help you get past your own insecurity to start breaking ice.
Once you get over yourself and stop letting yourself sweat it and worry about how some girl will react to you talking about the damn weather, or a movie you're both in line for, or whatever the ****, it will get easier. Practice makes perfect bub