Start early with the social skills.
Got to tell you -- you can only "teach" so much. A child I know, who is more socially impaired than my own son, had hundreds of thousands of school district dollars spent on him, and now in his early teens he knows all the right ways to interact properly with people. Eye contact, the proper questions and polite responses.
Yet the "spitzengefuehl" (fine-tuning?) is missing. He can't slip into the casual dance that is every natural human interaction. He doesn't pick up the subtle signals, even though he's been trained to "do it all correctly." I have seen lots of these cases and frankly, it feels good to admit that it's not a parent's fault for not getting enough social skills formal training. Social skills can only be learned to a point.