When I want to write a song, I often start by jotting down everything I think of when I consider the main idea of the song. In this case, for my novel Get Happy, my character Minerva wants to write a song about money. This was one of my brainstorms. I revised the song a bunch of times before finishing it. You can hear my original demo of the song on soundlcloud and also watch Jamey Geston’s version of the song.
Next time you want to write a song, try dumping all your thoughts down first before actually trying to write any lines. See if that process works for you.