I'm 30 and horrible at keeping friends. I don't know if it's the unschooling or the autism, but I'm told I come across as hostile when I think I'm being nice.
I know the basics. I make eye contact but not too much, I ask people about themselves and their interests to show I'm interested, I don't dominate conversations with myself and my own interests. I try to be a nice person people might want to keep around, too— I give money when someone's in a pinch, I remember birthdays, I help move, et cetera.
Eventually people either people tell me I'm being a dick in ways I never realized, or more likely, they just eventually stop messaging me back.
The one thing I'm sure I struggle with is body language. I've read a lot that you need to mirror the other person's body language, but I don't know how to do that. Especially since I normally meet people at work and we're usually pushing big carts around and moving products and I'm just not thinking about my body as something expressive, just practical.
I'm sure I have many more blind spots that I'm not even aware of.
So like... are there classes for this? Some kind of specialized therapy? I don't really want to try anymore unless I can stop being a dick
Try finding an open club with Toastmasters and go practice speaking and communicating with folks who are also there to practice speaking and communicating. That kind of space alone may give you the chance to see differences between their interactions and yours, but it's an incredibly helpful group for so many people who struggle with their communication in everyday life.
Toastmasters seems to be focused on giving presentations?
From their about page:
Yes, but those skills of effective communication are able to be universally applied, even in private conversation. The fact that it's a positive environment and one focused on constructive feedback is why I feel that it might be an avenue for OP