It helped a lot when we grade accelerated DD and suddenly she was with kids who were older. She went from being bossy to everyone to hanging out more in the background.
That said, she can still be a know-it-all but tends to hold it in pretty well (at least when she is on her ADHD meds). She is now 8. Her best friend is a boy who is over a year older and they are both into computers. They talk on the phone about computers and DD will say someting like "give me a minute, let me pull that up on the LAN server." I'll hear "What! What!?" Coming through the receiver, the kid has no idea what she's talking about. DD starts getting impatient and expasperation starts coming out in her voice. Pretty soon she just wants to get off the phone. That said, at least this kid is at least somewhat close and they have similar interests and things in common. I think the key is to try to find kids at the same level (even if they are older) but that can be very difficult. We have also done a lot of work on social skills, for instance you have to talk to your friends nicely, you can't boss them around even if they are acting dumb, etc.
