I tend to enunciate pretty well. It's always seemed that my voice is one of those voices that people can recognize pretty easily - which has been a bit of a drawback for some characters because you're supposed to lose yourself in the character, but sometimes people look at a character and go "Oh, it's 'Weird Al.'"
My own personal tastes don't really have an effect on whether song is a parody target or not. But having said that, I try to pick songs that I actually like because I realize that I have to live with these songs for a long time, from when I'm working on them in the studio to possibly playing them onstage for the rest of my life. So I try not to pick songs that I know would drive me crazy.
What kind of morons do you have working at newspapers in Austin that would base an entire review of an artist's performance on whether or not they had a good seat?
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.