Unironically practice in VR chat or something like it that's low stakes so you can just have fun screwing around and talking to randoms until you pick up how to not sperg out in social situations.

The real trick to know is that nearly everyone is also extremely socially anxious, and knowing that, you can fake confidence until you make it real.

The hardest part is finding groups where you can be totally unedited as yourself and still be wholly accepted. My strat is just make friends through hobbies and our similar interests helps make the inital connection that can be built on later.