Well for starters, your anglea aren't symmetrical left-to-right. Then, the lower half is too low (should be as thick as the upper half) and then you have a couple of small details that are off.

As for shading - first drop all the unnecessary lineart, for instance that of the main 'pyramid' shape, and then add some subtle highlights instead on those corners.
What you probably meant is that this object isn't very interesting, shadingwise. And it isn't, because it's all straight surfaces, no challenge.