After they have observed you for a while, someone will get up the courage to talk to you, and then you're pretty much taken in. It's embarrassing to admit the following, but how you look seems to be pretty important in how fast you are accepted. The goth scene is one of the few places that a plain girl or a femmy boy can become very attractive, with the right kind of packaging. It's really great to see these people getting a second chance at life. But it still seems to be true that if you're beautiful by mainstream standards, you can just stroll in.
Mopes are sort of a special case.
You're basically looking at the singularly most shy people in Western culture and they never chat up strangers. I belong to an ill-defined group in my home club, so as an insider, I can tell you that despite appearances, we are very interested in new people, and we make covert inquiries in order to collect information about them. Because we have no social skills and the anxiety associated with meeting new people is unbearable. There are ways of dancing that are identifiably gothic, but not one style. If you're a goth, you'll be able to identify a gothic style of dance, even if you've never seen it before.