I suppose you could always do a Google image search on "art deco" and pull out some interesting/general examples. You could pull em up on a laptop if you have one, or print them out. Or you could always take a trip to your local public library and look for some books on Art Deco (or the '20s/'30s) with some good photos. A public library is a great resource if you have access to one.
The Wikipedia article on Art Deco has some good examples of architecture, as well as some links.
I think setting is very important; a well-thought out, detailed, and consistent setting can be a real joy to explore and game in. Details are what immerse your players in the game. There's such a thing as too much detail though, and if your players show little interest in such details or start to zone out when you describe stuff, then you'll probably have to dial it back.
BTW, I think black powder weapons are a little too low-tech to fit in with a Victorian/Art Deco era setting. The revolver was invented in 1818, and the Victorian era started in the mid-to-late 1830's. It might be neither here nor there, but it struck me as a little odd. (If the transition to a more Art Deco-inspired setting includes more modern-type weapons, ignore the preceding
)
Ø
