Learn your craft, then tackle something you are really interested in. The basic components of writing really haven't changed that much in the last 500 years or so: building characters, telling story arcs, creating hooks, and so on. Read anything by Flaubert or read Don Quixote--nothing has really changed since. It's similar to being a carpenter--a chest of drawers or hanging a door really hasn't changed much, probably, in a thousand years or more. But to create a solid chest of drawers or to do a good job at hanging a door--you have to learn the basic techniques. Writing is no different.