I actually write more poetry than lyrics, but I would imagine that the manner would be the same, I have to be in the right mood for creating that stuff, and I almost dont think of the words, I'll be at work or listening to music and a word or line will pop into my head, I start with that, I just write without thinking, it sounds dumb and it's hard to explain, but if you focus on the words you're writing too hard, you end up using the wrong side of your brain (this is my opinion, any brain surgeons among you feel free to disagree) I do all my creative things, be it lyrics or poetry, or my artwork when I'm listening to music, thinking of other things, although there IS a balance, if you think about other things too hard you cant think of lyrics.
I can honestly say, that once I was drawing a picture, and my hand with the pencil took on a life of it's own, I remember looking at it and thinking 'why are you doing THAT' but the pic turned out pretty well.
I hope my mystical way offers you some ideas.. if not, you can always laugh at the freak......