I think whatever you do, you cannot exit your prison on your own, you always need someone who helps you to open the prison from the outside. If there wasn't someone to exit, you'd stay in there, locked. Only if you step up to who you are and someone accepts you for that, you will continue in that direction. If you get rejected each time, eventually you'll retreat further into that prison of yours.
Therefore, a change as big as a community gaining acceptance of the whole world, can never be a sudden change. Like the homosexuals 40 years ago, gradually grew in numbers and also became more common. So what I'm trying to say is: With every person that stands up for his believes, it is easier for the next one to do it in a similar way.
I agree with Julie though, it's the interactions that will bring about the change. I wouldn't be willing to agree with a person if this person if I don't get treated with respect. So whenver I try to convince people of something I believe in, I first try to gain their acceptance and respect.
That is also how I get out of my prison, when I feel that people respect me for who I am, I don't feel like I am behind any kind of bars that restrict myself.