Hey there! The main issue I see here is that the perspective isn't clearly established. The lines, particularly those of the buildings on the right, aren't converging toward the vanishing point and instead look straighter. First of all, you need to establish your horizon line so you have a better idea of where the lines should converge. Notice how this makes the buildings look more three-dimensional instead of flat. :) On the other hand, establishing the horizon line will also give you a better idea of how round or narrow the ellipses of the cylinders should be. As a general rule, the farther an ellipse is from the horizon line, the rounder it will appear, and vice versa. This is another reason why the cylinders looked a bit flat: the ellipses weren't clearly defined, particularly the one on the central tower. Another important thing to keep in mind, which will help you create a better sense of depth, is the overlapping of forms. This applies to both the castle structures and the terrain. You can also draw some contour lines along the terrain to give it a better sense of volume. :) Hope this helps!

