It's very cleanly drawn, though it could use some semblance of shadows to give it some depth and contrast. It's all very white, and while that's clearly the color of his fur and clothing, giving it some atmospheric lighting and bounced colors will make it much less stark white. But the most immediate difference you can see in your piece is if you make one direct source of lighting and give more significant shading based on the form of the figure, like under his cape for example, rather than just the type of shading where you use a little bit of dark gray around the folds and creases of his clothing. Push for darker shades in your shadows and try to avoid using just gray when shading white. The technical application of line, form, and coloring is wonderful; it just looks flat from the color choices made.