One of the exercises is to draw a tree. Then to go outside and look at a real tree, and draw what you see.
The two could not be more different.
Many artists will talk about when they "learned to see". Which means: understanding that reality isn't the simplicity of what our brain constructs, but rather the seemingly infinite detail of what is actually out there.
It changes the entire way you look at the world.
A bicycle is an incredibly simple visual form. You can doodle one in about five seconds. They're not rare or unusual objects and they're relatively homogenous. Nonetheless, most people have never actually seen a bicycle. They've looked, but they haven't understood its form, they haven't decomposed it into lines and shapes. They know that it has two wheels, a chain, a saddle and some handlebars, but they've never actually noticed the shapes that join them together.
In my very limited experience, I think this skill is made up of two components: finer details  and emotional expression. 
I find drawing to a be a great way to learn the art of going into finer details. For emotional expression in animation, you will need to study the classic principles of animation. 
On top of this we've built all these abstractions... like how to socially interact, how to recognize membranes as a face, etc. (also interesting: those with severe autism seem to lack some of these abstractions)
When buddhists speak of seeing reality or things as they really are, they speak of discarding these abstractions and seeing raw experience.
I started learning how to draw because part of the process is discarding these abstractions (oh that's an eye, I know how eyes look) and instead drawing in terms of shapes and lines: moving down, closer to physical reality. This book has been very interesting for this: http://www.amazon.com/Drawing-Right-Side-Brain-Definitive/dp...
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