One of the things that makes steampunk different from other genres of fiction is the diversity of arts people use to explore steampunk. Yes, some people dress as Gandalf or Darth Vader, but those are not the norm and they are merely copying images which have been given to them. In fact, steampunk is not really a genre, in a sense it is an art movement that crosses boundaries, unlike anything I can think of which came before.
Steampunk fashion is all about finding your own path. The variety of styles is as varied as the people who enjoy steampunk.
There is the punk-rock steampunk look.
To the more demure and traditional Victorian era garb.
To the decidedly more, "out there" retro-science fiction looks.
There is a look to suit anyone. And, unlike your Darth Vader helmet, much of it can be worn outside of a convention setting without attracting undue attention. Well, undue negative attention anyhow, it's hard to imagine anyone failing to notice that first one.
I have added a link to the links bar where you can find all the above pictures and more, take a trip over to steampunk fashion and have a look for yourself!