I think you oughtta go back to tracking. If your tracks are good, the mix will be easy. No mixing can fix bad tracks.
I think you oughtta go back to doing the arrangement. If your arrangement is good, the tracks will just come right out of the musicians. No tracking techinque can fix a bad arrangement.
I think you oughtta go back to songwriting. If your song is good, the arrangement will come naturally. No arrangement can fix a bad song.
I think you oughtta pick a better artist. If you've got a compelling artist, they'll bring home any song for you no matter what you do with it. No song is good enough to survive an uninteresting artist.