Steam- Brought Humanity to a new age, Didn't it?
Now how do you do Steam-Punk models? Well! First you have to have the seed of an idea. Here's a source. Go to Your Local Library and see if they have any Railroad books with lotsa photos from after or During the Civil War.
Now go look at Airships and Regular Ships and the really English trains. Also get some books on Victorian interiors into the fifties like open elevator cages in hotels and stores also. . Some of that stuff like Decorations on Buildings and Facades survived even longer. But You The Creator have to bring all of it together in a co-hesive design.
Last Tip--Autos from the early years. Many had flourishes in design that fits Steam Punk perfectly. Can you do it. Try something simple and then Have a Ball! Note: Old weapons such the guns like the Constitution has, even fit in. BlunderBusses and Flintlocks coupled with the parts from modern weapons too.