I’ve been etching glasses for a few years now. I’ve gotten pretty good at it, although I’ve slowed down considerably because I’ve given glasses to all my friends so what’s the point? Wait, you don’t have any glasses? Um, I’m ready when you are.
I use a special printer that cuts vinyl stencils, put the stencil on a glass, apply some hydrochloric acid paste, and then wash it all off. It has only taken me several dozen glasses to get this process down, but I can pretty much crank these out now.