Sing
your song. Even
if you are not a singer, be sure to always sing out loud any song that you write.
When you sing the song, you become more aware of the demands the song places on
a singer -- including the melodic range, the jumps between intervals, and potential
conflicts between phrasing and breathing. Don't worry that you don't sing well
-- the point is to get closer to the song from the singer's point of view.