Idk sh!t about songwriting, but the first step for me would be to get an idea of what im writing about, and then come up with some sentences about it, and then make them into multiple verses with rhymes. But idk really im just trying to help
Im a songwriter and what i do is i make a list of what want the song to be about and i test the beats to make sure it sounds..well..good
andi make sure im comfortable with it and it defines me