Try separating the vocal track into three channels. Pan on channel left and one right with the volumes down. On the panned channels you can now add a little reverb or low pass them to give them a higher presents in the mix. Also, pick out key words, place them underneath the main vocal and use delay and reverb. You can also add harmonics by pitching these key words up by 3, 5, or 7 cents. Whatever sounds best.
Hope this helps.