It's hard, really hard. First off because steam punk never really existed, and it's a small genre compared to many other "aesthetics" (sci-fi, fantasy, etc). Not to mention the fact that steampunk itself is a blend of Victorian Sci-Fi, so people tend to focus more on the Victorian aspect and ignore what differentiates steam punk from "Victorian inspired fashions" (I don't know either, FYI). Off the top of my head, the only real way to translate it into an actual, wearable aesthetic (wearable is a loose term here, but if people can walk out onto the streets in GothNinja style then I think we can be lenient on what is wearable) it would combine Victorian influences with a touch of WWII inspired influences (not military, but think of flight jackets and what pilots would wear). I don't necessarily think military is such a bad look.