Heh, you hit on something that is about impossible for a group of folks - those of us with Aspergers (or High Functioning Autism).
Social skills are things that are taught and learned, and for some of us, they just don't make a darned whit of sense! I mean, why would I look someone in the eye, when for every other mammal around, it's considered a sign of aggression? It doesn't make sense!
However, social skills are needed to get by and succeed. There are a LOT of good tips here (and I'm looking closely at them to incorporate into MY life). If you know someone who really has a lot of good friends and is a good person, watch their actions - watch how they communicate, listen, and try to see their nonverbal communication skills - watch what they do with their hands. Practice incorporating those in your life. If you mom says your brother was polite and you weren't, watch how he responds verbally and non verbally, and try to mimic and understand what he's doing (not copy exactly, but say, if he shakes their hand, offer your hand to the person to shake. If he makes talk, listen and try to remain involved in the conversation. When he says goodbye, try to give the same farewell.)
I still royally suck at social skills, and I still work hard at them. My new challenge is trying to learn how to manage meetings with peers and higher ups at work - NOT my strong point, but I will do the same thing - when I return to work, I'll present my challenge to my manager (who is excellent at managing meetings), and ask for advise and if I can shadow her to some non-critical meetings to understand her communication skills.
And yes, even though it makes NO sense to me, I still work very hard at looking people in the eye when talking. At first it make me EXTREMELY uncomfortable, but I'm starting to relax a little bit.
Good luck! (And purple hair rocks. I work with a girl who colors her hair a glorious fire-red, and I just adore her hair. Someone else just dyed theirs a deep blue almost black, and it's lovely. Of course, we're all in IT/Programming at work, so they slack on looks, and concentrate on brains
Lots of Aspies there!