It seems the general consensus is that most everyone has to work at a song to get it right (and I thought I was the only one who had to do that). I thank everyone for their input - it's been very educational. I'll be checking into some of the references listed here. And I've printed this thread for my "personal files," to look back thru when I've done a bit more writing.
But seeing that songwriting is such work, it has brought up another question, which can be found here.