Hey there,
We own and operate a very successful recording studio. Layering is multi-tracking as has been explained.

As others have also explained, the song demo needs to compete against other well-produced song demos. I've recently been able to listen to several of the top songs being plugged in Nashville by Tim McGraw's manager. Boy, they were so very well produced. The biggest thing which impressed me though, was the talent of the vocalists. They really made the songs. In some cases, the performances by the singers and musicians made the song sound stronger than it was written!

I've learned that to make a song magical, it's not just the writing. It's the arrangement, production and performers who bring the entire thing to light.

Best of luck,
Heidi

"And, in the end, the love you take is equal to the love you make." Paul McCartney