1:57 PM, Friday August 14th 2020
First off, for the sake of the ppl reviewing, please make an effort to center your photos on the page.
your ghosted lines actually look pretty nice! It shows a lot of potential and I only see a few curves here and there in the ghosted lines and planes. If you need practice with straightening or countering a natural tendency to curve, try this exercise. https://imgur.com/gallery/zdkHsmt
Basically superimpose a curve that is concave downwards. Then (without rotating your page) superimpose a curve concave upwards using the same endpoints. Then superimpose a straight line using the arc endpoints. The point of this is to allow yourself to exaggerate the natural tendency to curve, then get a feel for countering that tendency. Ideally, you'll be able to dial in between the tendency to curve and the counter curve to get a straight line.
Also, when you superimpose your lines, i recommend trying to not fray if you can. Based on your ghosted lines, I don't think you should be fraying quite as heavily as you are. Bring the mindfulness of ghosting into superimposing to get a more efficient warmup.
As for the corners of the rotated box, I think you need to think a little bit more about how the edges of the boxes converge. the boxes along the axis have 2 vanishing points, but the ones in the corners get really tricky because they actually have 3 vanishing points.