I think that while the composition could be stronger it still has a good impact on the viewing nature of itself. The only two qualities I would change about this are the ring and background. I think you could make the ring emit some kind of light around her or something could be added to make it more dynamic. A radial background put behind her could also bring out some of the dark parts of this picture like her hair and hands. Your coloring skill is great and your anatomy seems to be spot on which makes me happy on the inside. You haven't overdone anything on this piece and the highlights make sense(total winXD) Success
The terror this exudes and invokes a bit of in the viewer was the first thing that hit me here. The composition is great- difficult pose, dynamic without being too "actiony", and the way the lock of hair swirl down her is not only eye candy and good detail, but makes one think what this could be. The position of her hands, the look on her face, the way you did the eyes- all are fine details that bring the piece together. The ring is a bit crooked though, although I do like it- is she trapped or is this a planetary ring?, I ask myself- and the style the butterfly is draw in seems to clash with the way you did the rest of the piece. I like the glow you gave the butterfly, too, although it seems that the ring ought to have some sort of light too, since otherwise there seems to be no other light source, so it makes me think that the girl should be in complete darkness. Overall, this is a good piece, and definitely one ripe with "It could be this..." interpretations.
Good that you've got imagination. I know this I-don't-know-what-I-already-draw feeling Experiments are very important! I like way you draw outline. Shapes and colours are interesting, contrast between dark colours and white lines works very good! Really good picture in my opinion.