Reply by smallerstick

First post here; I’m a newbie!
I just moved up from an 8×12 shed to a 16×20 garage, insulated, 40A service and well lit. this is about the smallest I could work comfortably in, I think. I have seen much smaller and some of the quality work that comes out of them. I’m sure that 12×16 will be enough for you to begin accumulating tools and finding out how to arrange them and work with them.
As others have said; go with a solid floor of some sort. Depending on your location, consider frost and heating requirements. Concrete is solid, but cold in the winter. Wood is comfortable year round, but costly.
Allow for at least 1 220v outlet if you can.

I could go on but so much depends on what you intend to build.

good luck!

Peter

-- Peter