I don't know how helpful this is, but I usually base my worldbuilding on ideas for storytelling that are sort of woven together. What this means, I guess, is that I have some idea for a story (that I will probably never actually write) and that I think about what the environment that that story takes place in ought to look like. Then I take several of these sorts of things and put them together into something that's more coherent, modifying things along the way.
As for where the "inspiration" actually comes from, I'd say it's essentially just a mix of media that I like: I was a big fan of Garth Nix's Old Kingdom series, and I find compelling various themes, tropes, and interactions that come from novels, t.v. series, anime, etc.