One of Jason's suggestions is to keep a list of song titles. You should add to the list whenever you hear a potential song title.
That's interesting - the title is always the
last thing I write. Quite often I'll change it subsequently - for example the song I posted to the review forum yesterday was originally called "Don't Ask Me", but after I'd performed it once I decided that "Ask Me Another" would be a better title. Sometimes they come naturally but sometimes they're the hardest part of the song - there's one I wrote at Christmas whose title I'm still not happy with.
I mainly write comedy songs and there's a particular problem unique to that genre as far as I know. In most songs, if you have a repeated line that occurs throughout the song, it's natural to use that as the song title. If you do that with a comedy song then you've given away your punchline!