Looking good. My #1 recommendation is to not redo lines. If a line is wrong, it's wrong. Leave it as it is, and spend more time ghosting the next one. Also, in the planes exercise, the non-diagonal center lines of the plane should to go through its center point (the intersection of the diagonal center lines.) Because of the rules of perspective, it's not as simple as measuring the halfway point, and putting a point there, though I suppose you don't need to think about this just yet.