That cartoony appearance most often is a result of strong contour lines. When you look at objects in the real world(tm), there isn't a black line that separates them from each other. Punch up the gradients and shading a bit and lose the strokes, and I think you'll find your objects look much better. On the other hand, you'll need to find a different way to keep them from blending too much with the background and each other. Cast shadows will help with that, I'm thinking.