I'm really glad I started getting involved in organization/volunteering for events in subcultures I was interrested in from early on. Most of the time you don't need any particularly involved skillset apart from a pair of hands and the willingness to get to the event early.

I've been helping with preparing larps, carrying stuff on concerts and prepairing the venue, distributing flyers, picking up background playlists for the party, making small event websites, DJing or simply just handling the entrance ticket checking.

Most of subcultures that aren't commerecial-level of big (what I mean by that is ran by volunteers and usually non-profit), such as larps or smaller music scenes, need any help they can get, and simply being there with a few people before the event starts and being involved in helping will naturally break the ice with a few people from the group or scene, and it's usually people that will then introduce you to the rest. You also have something to do that's not only socializing, so it helps with social awkwardness, and you get free entrance and drinks or food.

It's the best tip I have about how to make friends, plus it helps the scene and at least for me, having something to do makes it more fun. I didn't really know many people from the scenes until I started working, mostly because I find it pretty difficult to talk to people I don't know, but now, after few years of helping out, I know almost everyone in the scene and consider most of them my friends.