Try Drawing through your structures so you can see the entire wire frame (all edges of the planes). For your boxes, break it down to a single flat plane, and just try rotating it like a piece of paper in space. Your lines should feel like they are slightly converging towards a point in the far distance. if you notice the far end of the plane/paper is diverging (getting bigger rather than smaller) than try again, and keep in mind where your intended vanishing point is, and subtly converge the lines toward that point. Sometimes it helps to exaggerate the converging perspective to get the point across to your brain. Sometimes it just won't look right and that's okay. I found it to just do multiple iterations on the same angle you are having trouble with rather than trying to fix the broken lines. It's going to take a couple of tries for your mind to get a grip on where things should be placed. So keep at it, I can see you getting the hang of it.