IMO this is very good! nice job.
Suggestions (matter of opinion at this point)
Little too much reverb on the orchestra strings/piano.. or maybe the reverbs are overlapping, ie at 0:50. Give each reverb its own space in the mix.
The dubstep synth could use a little more richness. Maybe some subtle distortion on the lows. Also some sounds could use a little more lows, like the synth at 1:30. If it's getting in the way of the kick too much after you raise up the lows, just use a side-chained multiband compressor to nail a few db on the peaks of the synths every time the kick punches. waves C6 works great for that.
Voice has too much autotune
on it at points. For the way she is singing (soft and gental) the pitch corrections should not be set to jump from note to note so abruptly, but should be set to slur a little more.
I don't really like the phaser or flanger you put on the vocals at 0:46 and at other parts. I think with her style of singing, her voice should be left alone again because of her singing style... and also because her voice sounds really good. It doesn't need to be covered up with processing.
The sub bass at 3:00 is awfully low in pitch. So low that it's almost making the mix sound mushy. If you made it higher in pitch our ears might be able to find it better.
Again this is all my opinion. But I still think this mix is very very good! Keep up the good work!