Pretty good idea...your masking could use a tweak, and there are small dark artifacts on either side of the disc thing, which IMHO you could do without.

I agree with CMYK about the disc thing, doesn't add to the image IMO. I would try and correct the perspective issues between the rhino and the wings, the wings look straight on and the rhino is sideways.

Thank you both for your feedbacks!
I made some changes..hope it looks better..

LOL...find a real rhino...plastic just doesn't make it.

You've got the makings of a beautiful piece here. Couple of points: 1. Ditto CMYK. Either find a real one, or make this one look more real. 2. Masking of the model could use some improving to soften sharp points. 3. The sky would not pass in front of the tree, so you might want to erase the sky there. Good luck!