Lean thinkers are intuitive
Intuition can be developed through practice and immersion. Practice is doing the same thing so many times that you no more know that you know. Imagine how Roger Federer swings his tennis racket, without thinking and knowing how exactly he achieves whatever he achieves!
Immersion means such a deep experience that it enters the implicit memory and stays firmly lodged without your being aware it is there. It equates with what sports psychologists call "flow" or being "in the zone."