Very nice job. The biggest issue here is the lighting. The piece is a touch too bright. But this is an easy fix. I assume your using PS? If so, create a new layer. Now choose your brush, try a round brush around 200-250 pixels for size and drop the hardness to 0%. It's very important to get a nice soft brush for lighting so you create tat fade away effect when changing layer settings later on. Now brush some black around the bottom right and bottom left, go a little higher on the left though since the effects are bigger and angled more. If you don't think the brush was soft enough at 0% hardness then simply go into your filters and blur it a bit. Not too much though, you don't want to blacken the whole damn piece. Now set that layer to overlay or soft light and tone down the opacity accordingly. You don't want it too dark. Hope this helps.
Also, if you want I can CnC all your pieces but you have to join [link]