There are many books on the subject of songwriting and it seems that each one has a different way of approaching it. What you might not hear often enough is anyone suggesting to “just do your own thing”. There are many “methods” and “systems”, but in actuality, they are really just that composer’s way of doing their own thing.  Sure, the song has to make sense and people have to be able to access it.  In that regard there are similarities among many contemporary songs, whereas they all have verses, choruses and basic song structure.  This is where the craft of writing a song comes in, because writing a contemporary jazz song or any song is a craft and an art.