Shading, it's all about shading. Your painting seems quite neat, but a simple black wash over the metals, a chestnut wash over the gold and some shading on the claw type thingy will transform your miniature. Something very interesting is going on with his right knee, not sure what, but it looks interesting. One more very important thing: remove those mould lines! Few things can destroy a miniature as quickly as a mould line.