"Coolness" is one of those elusive unspoken concepts that is a problem for many people with ASD to keep up with. It involves many rules of speech, hobbies, dress, and mannerisms that constantly change over time. It's not something that can be easily taught. One of the paradoxes of "coolness" is that as soon as it can be identified (lets say a fad or fashion), it has already moved on. It is an elusive concept related to Zeitgeist which is German for "time spirit" or "spirit of the times". The Zeitgeist is far easier to understand when looking back and reminiscing. I'm in no way implying that being cool, popular, aesthetically pleasing, or aware should be a priority in and of itself. There is nothing wrong with being a geek and I cartainly don't imply that everyone needs to have the aesthetics of an Abercrombie model. To a point though we have to have some awareness in order to avoid problems.
Some extreme examples, in colonial times there was nothing feminine about upper class men wearing wigs. If someone wants to do that today, more power to them but it may some with social consequences. For a long time in the early 20th century, long hair in men was considered eccentric at the very best. In the 1960's and 1970's it became more popular among young people while older people saw it as disrespectful enough to deny someone a job over. In the early 1970's decorating a home in harvest gold, avocado green, burnt orange, shag carpeting, fake wood paneling, stolen street signs in bedrooms, bars in the basement, dartboards that never get used, gaudy floral wall paper and front porch furniture, and fake greenery was the thing to do. Generations later it became the butt of many jokes and sometimes a nightmare for real estate people, designers, and landlords to work with. In the 1980's many people had big hair, mullets, shoulder pads, high shoes, pants pulled up to the chest to look tall, men getting up just as early in the AM as their sisters to style their hair, short pastel colored shorts, cars overloaded with flamboyant accessories, Jordache jeans... Some of this lingered into the 90's in parts of the US. Today however, what was cool in 1984 can lead to some very negative attention unless your one of those people who know how to pull off anything. When many people look at their parents' high school yearbook and see which kids were considered cool or the major heart-throbs would be the laughing stock of their high school today.
I am a firm believer in individuality over conformity, however I like to see everyone, especially those with ASD to understand what is going on to avoid getting bullied. One thing I learned early on is what one thinks looks cool on someone else may not work for another. Many styles, jewelry(especially on men), tattoos, mannerisms... that look "cool" on a well respected acquaintance may be meant to make a certain statement relevant to a particular subculture and may cause someone imitating that to be severely misunderstood. It seems this is most pronounced in the teen years and early adulthood, where rules can be quite complex and people struggle with trying to find the perfect balance between conformity and originality (a very thin line). Many times people just wake up and wear whatever feels comfortable with no intention of making any statements, but it doesn't mean people wont try to interpret a statement out of us. All too often, people get bullied and don't understand why. If they do something eccentric people end up blaming the victim and thinking they were trying to draw attention to themselves and have no sympathy. Many times these are the same people who won't give helpful advice.
Another strange irony of "coolness" is that if it is revealed that one is trying to seek it out then they are anything but cool, therefore I don't recommend for people to try to be cool. I do however recommend basic self awareness. This is something that needs to be taught by loved ones and won't be part of any formal social skills or "etiquette" training.
Here's a link to some excellent Wikipedia articles on Zeitgeist and Coolness including a profound quote from Bart Simpson. http://en.wikipedia.org/wiki/Zeitgeist, http://en.wikipedia.org/wiki/Coolness... And here's a very entertaining blog about the 1970's styles from today's perspective. http://my-retrospace.blogspot.com/2010/08/that-70s-home-6.html.
BTW I'm not sure if Einstein was ASD or not, but he may be an example of someone who made a much bigger difference in the world than the average pop-culture icon. Yet going by his pictures he wasn't what many would call aesthetically savvy. Cool people may get more esteem when they're alive but geeks seem to be better remembered in the long run.