Innerviews has an in-depth interview with guitarist Leo Kottke. About his writing process:
There's the tune and then there's the writing that has been going on in my head since I first made up an E chord. Immediately, I was doing what I'm doing now. In the beginning, I was just trying to make sounds. That's all I'm still really doing now, but I've learned a lot. This arc continues and I fill it out more. I have a bigger appetite. My curiosity keeps growing as well, as does my technique and execution. Curiosity is the engine for just about everything with me. Someone who's like Donald Trump is out of luck on that front.
Since I was 11, I recapitulate every time a tune starts showing up. It would show up as a figure, progression or a verse. It could also be as simple as hitting early on the overtones and fretting afterwards. Michael Hedges told me what got him going was when he heard me doing that. But what he did was a universe away from that.
When you play something you like, you want to hear it again. So, you keep playing it over and over and over again, because now you're happy. You know something else has happened.
Eventually, it might become a tune. There's a phrase that goes “ontogeny recapitulates phylogeny.” That's the best way of describing it.
On recording the Noon album with Mike Gordon:
Mike is a great musician and fully fluent. He's done all his homework and he's knowledgeable. He can play what he thinks. That's part of the experience. But at the heart of it is the friendship and the feel. When we're playing together, our hearts are on our sleeves. We're very vulnerable. It's rare for musicians to be total assholes. They're not people you want to play with, no matter what you think of their music.
So, it's the ordinary stuff that we all live with and go by. Proprioception is the sense of how close you are physically to another person. It's what allows you to walk through a crowd without bumping into everyone. Proprioception extends to something we could also call our crap detector. If your crap detector goes off, you're not going to play with that person. There's also something else in you that goes “Oh, this is cool.” And if you happen to be musicians, songwriters or composers, you may do something together. That's where Mike and I are at. Sometimes we're doing something and it rises up. We don't sit down and agree to do something. Whatever is going to happen is there before we have that sort of agreement. You don't know when it's coming.