Also — not to make this too huge of a rant, as I plan on putting this into a tutorial eventually — while you are learning these techniques, it’s a good idea to keep in mind a balance between accuracy and readability. This particularly applies to three-point perspective, and as such is the only reason why I am mentioning it. Three-point is more of an abstract form of a grid, so if you try to make it exact and precise to your vanishing points, it may not look right. Sometimes it helps to make the vanishing points “approximate,” in that they are general points to shoot for, not necessarily a precision target. This may help with the readability of your scene and actually make the whole process a LOT less stressful on your part. Heck, even try taking a ruler to my first panel up there. I can pretty much guarantee that only one or two of the vanishing points will actually line up (as I did it by sight, instead of measuring it out). It’s still perfectly readable though, and — particularly in the comics universe — that is what counts.