I've written most of the lyrics for that song that I have been mentioning in the past two weeks. I pretty much just have one verse to go. For this song, I started writing the vocal melody around the same time that I started writing the instrumental parts. I worked on the vocal melody both consciously and subconsciously as I wrote the instrumental parts. During the time that I was doing that, I also thought about and chose the subject. By the time last week came around, I had a general idea of the melody and I had the subject. It just took a few steps to turn the general idea of the melody into a definite idea. Writing the lyrics now is a matter of choosing the words that express the subject and fit with the melody.