Recently I was talking to a songwriter friend of mine and he told me that he was working on a new song. I asked him what the title was and he said, "The title? That's the LAST thing I worry about!"
I found this remark very telling, because while there's nothing necessarily WRONG with coming up with the title last, I couldn't help but think how important a good title is, and how often a pop song will flow easily once the title is in place.
From a writing standpoint, a good title crystalizes your concept and helps you to focus your thoughts. It's usually not a good idea to write a song if you don't have any idea what you want to say! That's not to suggest you can't write a song by just scribbling lyrics and letting them take you wherever. However, that can also result in a lot of lost time wandering in the forest, and it's not a given that everyone's going to follow you there.
A good pop song title is - more often than not - clever but not pretentious, simple but not simplistic, and intriguing but not overly confusing. The ideal song title tells the listener in a few concise words, "Hey, we're going somewhere really cool, you wanna come?" Of course, there are some important exceptions and subtle differences from genre to genre,* but in general these "rules" almost always apply.
More to come…
*I know that country songs, for example, make frequent use of puns and wordplay (stuff like "She Hit the Road, He Hit the Bottle"), which is something you might find a bit contrived. Similarly, prog-rock musicians use long, elaborate, and "spaced out" titles. These variations tend to work well within their respective genres.