I didn't know drawing a single room realistically would mean that much work...
It does have a lot of math beneath, doesn't it?
It does have a lot of math beneath, doesn't it?
There is a lot of math behind it, but I am a little sheepish to admit that I probably shouldn't have picked a composition where the feet couldn't be seen. Had the ground plane been visible, it would have been much easier and more straight forward. I'll try to plan a little better when I do a tutorial on 2 point perspective. 
I would love to see one of those 2 point perspective tutorials done with realism.
I'm not that good at realism, but if you mean with non-anime characters, I'll keep that in mind.
As you get better at it, it goes by much faster and you'll be able to eyeball a lot of things. This tutorial series covers eeeeverything explicitly, but most artists do most of this implicitly. The important thing is to understand the three-dimensional spatial relationships between the things you're drawing.
You mean composition? I such at that, reason of why I'm following these tutorials. If you know some place on which I could learn that, I would be thankful.
Composition is a distinct but related concept. Composition (in the context of 2D art) is the 2D, non-spatial relationship of elements as they appear in the image. Ideally, the composition should be interesting and the spatial relationships should make sense, but in practice often one has to be sacrificed for the other (usually composition wins, since a poor composition is more noticeable than fudged space).