We found with our 2E boy (now 10) that we needed to cultivate the skill of being interested in what interests others. This didn't mean shutting off his own interests, but reading situations: realizing that other children on the playground may not be interested in obscure astronomy facts, and recognizing that their games are fun too.
We made it a priority to put DS into situations where he could learn this skill set (Cub Scouts...) and to work on at least knowing the minimum about locally important topics (football...). We are seeing a huge payoff on this investment. He is still him-- still wildly interested in things his peers have no interest in, not going to be a football player or win any popularity contests-- but he is much better at hooking into conversations and making social connections.
For the stuff that really moves him, we did find a high schooler to serve as science tutor this year-- more peer-like than mom or dad, and a great role model with whom to talk freely about high-level topics.
We are hoping as he moves from elementary into middle and high school we will be able to find more like-minded peers. But we are happy that he also knows how to engage with other kids, regardless of interest. We think of it as "protective coloring."
DeeDee