I'd say there is probably a book out there for anything you're striving for. Fantasy watercolor art, figurative watercolor, urban watercolor, so you should go for one that is covering the subject you like most! I'm a fantasy lover myself and I'm a big fan of the books by Stephanie Pui-Mun Law, I have 3 of them and they all begin with basic tools, and techniques before getting into painting full works. Good Luck!