I CANNOT just focus on one song. I keep writing little bits of lyrics that I just never finished. I could be writing ones song and then some new lyrics pop up into my head that just dont work with that particular song but are still good. Then I add on to that, then sooner or later i end up with a bunch of little baby songs.
There are plenty of other threads on writer's block with good advice. You could probably look in those.
that thread is full of win.
Listen to this.
That thread needs to be stickied.