I don't dress goth anymore, but I used to, I only stopped because it was making me depressed but that's besides the point. As an (ex) goth girl, usually we would prefer a guy who is also alternative, maybe a metal head, another goth, or maybe a punk. Alt people (usually) also like alt people, so you should look into some alt clothing styles, hair styles, and maybe even get some piercings. Another thing is to not be a poser. If you want to date a goth girl, you are going to want to listen to goth music, or other alternative music. Don't just dress alternative, actually be alternative, that way you have more in common with her. Finally, and I can't stress this enough, don't always expect her to look like a 'goth vampire mommy' 100% of the time. Goth make up and clothing takes A LOT of time and effort to put on every singe day, so there's gonna be days where she doesn't feel like it and might dress more 'basic'. To find some places where a 'Goth girl' might be, try music shops, thrift stores, the mall (specifically in Specer's and Hot Topics), goth night clubs (those exist, if your old enough to visit one and you have one near you, try there), and honestly just anywhere. I've seen alternative people many times in public, even at places like Walmart, you just gotta keep an eye out. And if your wondering how to talk to them, just treat them like anyone else. There's no point in gawking or staring at them, just be polite and try and have a conversation. That's about all I have, good luck dude.