Acrylic paint, color pencils, india ink with a quill pen, and a lot of tea.
The pose I used is based on the piece by SeanE, mistermoster, and macuy19 : [link]
I simply wanted to make a poster for myself, so I made a more vintage-feeling version for my room, adding in some Market Deco lettering, and the exploding zeppelin because let's face it, airships are sweet.
I had a lot of fun making this. I used watered down acrylics on the background, which I then stained with a ton of tea. After that I used a quill pen to ink in all the shading, then used a standard set of colored pencils, and finished with some additional tea stains.
I am planning to make some more of these based on other characters this summer. Hopefully they will start being made soon.