Learning About Perpective Points

Yesterday I was looking through my work from over the summer and I noticed that most of my drawings were from the perspective of looking straight on at the subject and that a lot of my portraits look a bit flat. Wanting too improve this I did some studying and spent two days learning about and practising using perspectives, the following is a summary of what my findings;

Reading "How to draw comics the marvel way" when I was about 11 I skimmed through a chapter on drawing heads, in a nut shell it said that heads should be modelled around cuboids, without reading much further or thinking into it (I'd only bought the books for pictures of super heroes) I tried this out, below is a reconstruction of what I thought the book meant...

The cuboid above is how everyone gets taught to draw a cube at school and its what's called "false perspective, notice that every angle (if it'd been drawn accurately) is a right angle which is impossible. Below is a cuboid drawn with 3 point perspective the bottom sides are smaller than the top ones as they are further away.

I then spent the day finding pictures of people to draw in 2 point perspective (as if you were looking at them but there face was looking to the side). I spent 5 minutes planning and 5 minutes drawing on each portrait, below is a selection of the practice drawings.

Now I'm learning 4 point perspective which I think is going to really help with my life drawing, I'm trying to enhance my drawing abilities as much as possible before I start Uni again in November.