Hmm
Make her do harmonies of her voice. Up and down an octave etc. If she can't make your own harmonizer track and blend it in just a little.
What I've done before is place main vox center, and pan different effects and/or harmonies left and right.
On parts you need to be stronger (eg chorus,) do what Mutt Lang has done so many times --- use a synth to back it up. Some nice triangle wavey stuff or stuff with a nice harmonic. Add reverb.
Perhaps EQ up above 15k just a tad to try to get breathing sounds in... Compress.
Let's hear some of it...