The second in our series of 14-1/2 tips for writing quickly.
Don't get yourself fully committed to any one idea you're working on. If you're stuck on an idea, and the idea starts to sink, then you'll sink with it. Sometimes the song you're working on just isn't ready to move forward. If it doesn't want to move, it won't help to poke it and push it!
It's better to stay light on your feet and willing to jump to another idea. You can come back to this first idea some other day.
Similarly, in the middle of a song, don't get stuck on any one approach. If the music isn't working out, start over with a different tempo or a different rhythmic structure. If you can't find a word that rhymes, rephrase the previous line so it's easier to rhyme with.
Writing a song is like solving a puzzle, and until the puzzle is solved, all of the pieces have to be free to move.