Wood is too shiny, metal could use some variation in colour and maybe some more detail, at the moment its kinda plain and one flat shade of grey. If that shiny wood is supposed to be old oily/waxy wood it needs brighter/lighter wood on the exposed most outer surfaces and darker crevices and more color variation. In general you should get some more color variation on, one hue for one material doesnt cut it.
What game is it for? Your game or some skin for a game? Looks a bit like a tf2 weapon skin. If its for tf2 you should get rid of the smaller ripples detail in the wood and add a few brush strokes, paint the dark crevices with a somewhat hard edged brush by hand.