I make charts of songs that are good candidates, good targets, so to speak. Then I try to come up with ideas for parodies. And 99% of those ideas are horrible.
In a genre where most of the artists are one-hit wonders, I've been able to hang around longer than most "serious" acts. I pride myself in being a very talented leech.
I do original songs in the style of other artists, where I try to learn all their musical idiosyncrasies and try to do something that sounds like them and yet is a bit more sick and twisted.
It was difficult to get into my friends' rock bands when I was a teenager. They somehow didn't see the need for an accordion player. That's when I realized that I had to find my own path in life.