Nice Work!
I picked up a few tips at the Dundjinni user art forum while making this type of object.
Here is a rework of your throne:
Attachment 11445
The only difference is in the shadows. I reduced the overall outer shadow.
Keep it a bit closer to the object then you had. I lightened it at the back of the throne, cause higher objects tend to cast a less distinct shadow.
I added shadows across the seat font and arms to give more illusion of height above the base.
I shaded the left and right of the base slightly to define the corners to the front.
All of this was done with new layers (the extra shadows/shading) or layer masks (reducing the existing shadows) to make it effectively "non-destructive" on the original image.
-Rob A>