There are two old threads on this topic, if you want to go back and eavesdrop on a few writers trying out lyrics and ironing out the wrinkles (or putting wrinkles in, in some cases): Songwriting 101 and Songwriting 101 (part 2). They are actually two halves of the same thread -- before this spiffy new version of the 'Cat...

And I also agree with Jerry -- Play with language... have Fun!!! Imagine that sentances, and paragraphs and stories, and all that, are great big jungle gyms to climb around on (or swing sets, or slides, or merry-go-rounds) and just let loose!!

To quote one of the best songs ever, from Joe Raposo (who wrote for Sesame Street): "Don't worry that it's not good enough for anyone else to hear -- just sing (write) -- sing a song!"

Cheers!!