Gotta do the listening.
I’ve written more than once about jazz being an oral tradition – to speak the language, you’ve got to fill your ears with the great recordings. That’s how you learn the language.
The thing is, it’s not just jazz. Every style of music demands a massive amount of listening if you want to become proficient. That is true even of the academic music that we teach in theory classes: the music you might think can be taught without the commitment of dozens of hours of listening.
If I want to write a two-part invention for music theory, as many music students are asked to do every single year, I need to have listened to 10 or 20 hours of Bach inventions, until I speak the language well enough to imitate it. (This is, to be clear, not a native language for almost all of us.) Without that listening, those project will fail to be anything but passable. Those students who have played inventions – piano students, mostly – will do the best, but no one will write a really great invention who hasn’t spent much time listening to them.
The same is true for every single aspect of music school mastery – including the music students study for their applied lessons, the music they learn to recognize for music history classes, and the stylistic choices they need to make in their ensemble work.
Without sufficient listening, you’ll never make it.