I learned my social skills mostly through observation and trial and error. I'd watch other kids in school, see what kinds of body language they used in specific social and emotional contexts, and try to figure out how other people reacted. Ditto for tones of voice and word choice. I also spent a lot of time mentally mapping out social relationships between my peers in as much detail as I could and tracking them over time, but I don't think that part yielded too much in the way of useful skills or information.
Whenever I thought I had some small piece of the puzzle, I'd find a context in which I could try it out, fail horribly, try to figure out what I did wrong, and try again. Once I'd realized that the only common element in all my social failures was me, it took me maybe 2 years to hit a level of basic competence, with gains coming slower after that.
I also benefited from bouncing ideas off of a therapist on a regular basis, though I suspect any sympathetic adult would have been about as helpful; the most useful part was being forced to clarify my thinking in order to coherently explain it to someone else. And having a low-pressure test environment didn't hurt, either.
A couple disclaimers:
Hope that helps.
It does somewhat, and I appreciate your experiences regardless because they are interesting data.
Personally, I have enough experience and innate skill that I am fine with the hard competencies (those social skills required to blend in, without which one really stands out). What I'm hoping to improve upon are those soft competencies that fill in the gaps between being able to handle social situations and being an empathic, social individual.
From my understanding, people on the autism spectrum have difficulty reading people's emotions and general social cues. I'm curious how these people develop these skills and what one can do to improve them. I ask this as a matter of personal interest; while I am somewhat neurotypical, I feel this is an area where I am very lacking.
(Sidenote: would this be considered an appropriate used of the discussion section?)