The other arts and sciences are viable places to start. The practice room and the music theory classroom are not. Lateral thinking, brainstorming, and sometimes general silliness lead the way to new insights about existing tools and techniques and beyond to the discovery and application of unimagined processes. Some pedagogical models are already available in the work of people like Orff, Kodaly and Suzuki. However, these models focus ultimately on mastering performance technique.
None have the making of original music as their primary focus.
A few alternate models for musical composition hover from time to time around the edges of the marketplace but fade because their paradigms are unfamiliar or misunderstood. In particular I would like to cite the work of Morton Subotnick, Joel Chadabe and David Zicarelli as champions of new paradigms. In M , Zicarelli and Chadabe define a world where musical process supersedes the laborious placement of individual musical events. Musical material is subjected to many methods of transformation. On its own, each method is simple and intuitive.