Have you ever drawn an entire picture, or painted a scene, to step back and realize that you've captured details that you didn't even notice were there while you were drawing it?
This is what I've heard referred to as a creative, or artistic zen.
You're capturing a landscape or a bustling city scene, and it has become almost muscle memory. You're no longer consciously looking at your reference for details, or at least not to the same extent you were years ago.
Many think that it takes years of practice, grinding into hundreds of sketchbooks.
More than once have I come across artists who draw rarely, but seem to improve in leaps and bounds whenever they do draw. Equally have I witnessed artists who have gone through several tons of paper over the course of their lifetime, to have progressed very little.
I believe that it has less to do with practice, and more with putting yourself in the mindset. Practice helps, for sure. You learn how to use the tools properly. I doubt hand-eye coordination is an issue, we unwittingly teach ourselves hand-eye coordination every time we play a video-game or spend time using the computer (among other activities). But to capture the image itself, it is more in the state of mind.
There are 3 factors involved in this state of mind.
1. "Lose your boundaries"
2. "Throw out your clock"
3. "Become out-of-touch with reality"
I'll elaborate on a future date. Just thought I'd start it now.