The FIRST thing every artist should learn

In order to learn how to draw well, we have to learn many art fundamentals, such as form drawing, perspective, anatomy, color theory, and much, much more. But before any of these things, there is one thing that I think artists should learn first: and that is observation.
  / pikat  

But I never had formal training in art, which is why I managed to miss this one completely...

Music:
Professor Layton's Theme (Live Version) - Professor Layton And The Curious Village Soundtrack
A Calm Afternoon - Professor Layton and the Last Specter
Puzzles 6 Deduction - Professor Layton and the Last Specter