I like the track. No offense to your singer, but I agree with the comments above about pitch problems in the vocals. Don't get me wrong. she is clearly a talented singer with a very good voice. With adjustments to the monitoring and another few takes I'm sure you could get a solid vocal track. With the one you have, though, you can work and work to make everything else sound great and even make the vocal "sound" great, but it will still be out of tune. This (Great!) song is kind of "about" the vocal, so if that's out of tune, it going to make everything sound off no matter what else you do. I know you said you're working on this for practice with your recording/mixing process, so it may not be worth it, but a way you could fix this vocal track without buying a plugin for your software would be to download Reaper, export a .wav file of just the vocal track, import it into Reaper, apply the ReaTune effect to fix the pitch issues, render the corrected track as a .wav, and then reimport into your software. (I don't know anything about Cubase, so if .wav is not the best format for moving it to/from Reaper, I'm sure there's another format that would work). ReaTune isn't a particularly good pitch correction effect (at least not in autocorrect mode), but its FREE (well, ok not free, but shareware, so...ya know...) In manual mode ReaTune works very well, especially on long notes that are just a little off which is what your track has a bunch of. If you want to go this route let me know and I can give details of how I use ReaTune for exactly this situation. It isn't obvious at first how to use the manual correction mode.
J