The quickest and easiest was to cover card with foil, run through an embossing folder and grunge up - the only folder I had that approached steampunk was a Tim Holtz clocks one, so that was duly dug out. It embossed beautifully, but just didn't look right to me - definitely seemed to be something missing, so I tried again using dark grey coredinations card, which I inked and sanded down, then added a butterfly cut from the original foiled pieces using a freebie die.

The suggestion I liked best was simply to stamp something and grunge it up - now that I can manage! I remembered buying a set of mini stamps ages ago for the lovely tree images, and not using the rest .............I stamped the crackle and hessian texture stamps from mail art randomly across the cream card using SU crumb cake ink, overstamped with a script and the tunnel from mini scripts in early espresso ink, finally with the cyclist from curiosities in black versafine twice. A hefty smudge of vintage photo and black soot distress inks and some roughed-up edges to finish.
Not sure that either of them are really steampunk, but they're the nearest I'm going to get to it!