Sometimes in writing a song I'll get a fabulous "stub", a musical idea, and rush to the piano to work it out into a full song. Nothing else matters -- I sit there, working as in a dream, focused on extending the idea, making it bloom, getting it to conclude. I am so pleased with it, I put it into the computer and make a nice copy (for the manuscript in these cases is a work of art - by Jackson Pollock!)
Then I take it to the piano and sing from this perfect copy -- uh-oh, more changes. I take it outside and sing the melody to the open air. Whoa! Places that seemed inspiring when the chords were in the background seem lifeless when just the melody is going, a capella. Or sometimes I find in the quiet of the day that the melody and words were not really married, but only cohabiting the same line on the page.
In the process of creation, I sing it dozens, perhaps a hundred times even -- so I have "practiced" the difficult places, and no longer consider them hard to sing (and sometimes get a rude surprise when others try to sing my song).
Sometimes a song has an "atmosphere" that I like, but all it is is an atmosphere, not a real song, something that makes you want to sing it over and over and over, and makes you want to go into the Word and study, and go out and live its principles. It can take weeks after composition to realize this.
How do you test your songs? I'm curious. Do you sing them to your spouses, do you create them as a group and "hash the thing out"? Do you write and then let it marinate so you can view your song in reality, after the intial excitement has faded? Do you just go with your first impression, the "fresh-baked bread" approach? What's your take on this?