Glenn Frey, and Jackson Browne lived in the same building for a time, and I have seen video of Frey crediting Browne for teaching him to write music....basically by just paying attention to Browne's methods, A lot of people have no clue, that one of the Eagles biggest hits (Take It Easy), was a Jackson Browne song, he couldn't finish, so he enlisted Frey to help. In fact, he had a lot to do with the Desperado album, my favorite Eagles album, and he is one of the cowboys on the cover of the album. Another guy, J.D. Souther, I think his name is, was in a good western, called "Purgatory", with Eric Roberts, and Sam Shepard.
I believe I got that info from the Eagles documentary, "East Of Eden".