It's easier to make a great song sound great then to polish an okay one. I'd venture to guess that if I were to ask you what's your favorite production or mix it would probably also be a great song. I don't know many people who like the production/mixes on bad songs. This is one of the biggest difficulties with new clients, having them pick a song to reference specifically for the sonic characteristics of it and not just the songwriting.
Great songs grab us and bring us to a 'space' maybe emotionally, maybe mentally, perhaps both. This makes the job of the engineer so much easier, because you don't have to try so hard to illicit a response from the listener, the song already does that.
This is where I would invest THE MOST of your time in the production stage,
write a great song.
Tip: I once heard a quote from Nashville songwriter, Monty Powell (Keith Urban, Tim McGraw, Billy Ray Cyrus) say to write your song and then look at it again and work the weakest section to be as strong (if not stronger) than the strongest section. Then to look at the new weakest section and revise that till it's as strong or stronger than the strongest section. Do this through the whole song for as long as you can. Walk away and revisit all your revisions and evaluate what you have.
