2♦ Two of Diamonds in The Rock Songwriter’s Deck: 52 Ways to Write a Song
The Two of Diamonds' suggestion is the opposite of a shortcut. You might call it a detour, or "taking the long way around." It's a zig, followed by a zag — a two-step process.
Step one: Pick a familiar song, and write all-new lyrics that fit its melody. People sometimes call this process "writing a song parody," but the goal this time is not humor or parody. Instead you're trying to write credible lyrics that fit a proven, successful melody.
Make sure that no traces of the original lyrics remain in your new lyrics. Changing every single word isn't necessarily good enough. (If you show the lyric sheet to someone and they can guess what song you started from, then try again.)
What you have at this point is a song with a melody owned by someone else. If you sing it for anyone, they'll say, "I know that song, but you're singing the wrong words." Whatever you do, don't stop here. Proceed to step two.
Step two: Write completely new music to your new lyrics. Don't just change the notes. Change the rhythm, the tempo, the key, the chords, the groove — everything.
It can be a mental challenge to forgot the melody you started with and think of something entirely different. Here's a way to skip that whole struggle: give the lyrics to a collaborator who has no idea what song you used as your starting point.
When you're done, you have a new and fully original song, and it only took twice as many steps as writing a song from scratch.
In practice, the Two of Diamonds' method most often is used by accident. A songwriter starts singing along with a song, and new words spontaneously suggest themselves. Before you know it, you have a new song in the works.