One exercise I have read about in a couple of places, which I am just trying out for the first time this weekend, is to take a song you know “ish”, but not so well that you know every single lyric, and then try to write it yourself without looking at the actual lyric.
The logic is that as you go through the various decision points of songwriting, you will effectively have a master songwriter right there to mentor you through it, as after you have made your attempt you can look at what they did and have immediate feedback on the things you could have done better.
To take chess as an analogy, the way you become a grand master is to go through expert games and try to predict what moves are coming next, again then having direct feedback as to what a better move might have been, allowing you to really get inside the mind of the master. It is exactly the same at art-schools, where students will spend time replicating famous paintings.
Anyway, is this a developmental technique anybody has ever experimented with? I will report back with how I find it!