03-21-2016, 08:48 PM
I agree with BrushNoir, the values are little lacking (super cool piece though, you've got a nice harmony of colours!). Something else that might help is adding more hue variation. If the light in your piece is cold, try using warmer toned shadows (and vice versa). Try painting with a large soft brush on multiply and a low opacity with a warm hue selected for the shadows, and on a separate layer, use the same large soft brush/low opacity, but this time on overlay or soft light, paint in some cold highlights. It really helps add depth!