I also would like to add that it's always a good idea to put at least 3 colors in something like this -- one color for the base color of the 3D form, another for the plane facing closest to the lightsource direction, and a final one to either emphasize the shadows, or in the case of a black object, to do some transitions somewhere.
Additionally, remember that nothing is ever completely black or white. If you look at any japanese anime, you should see that most 'black' is actually purple, and where they want it to be particularly dark, they add something closer to black (but still not black). This gives you an opportunity to add shading and 3D form.
Next time you post something like this though, it'd be a lot cooler to provide some explanation for what you were going for.