For doing the Classical form its about concentrating on FEELING the centerpoint of the fingertips on the string. Feel the EXACT CENTER of GRAVITY as you place the fingertip on the string. Close your eyes and concentrate/meditate/focus on that until you "get it."
You pick up all 4 fingers at the exact same time and PLANT them on the next four fret spaces all exactly at the same time.
Imagine if you played FRETLESS bass or even FRETLESS guitar - you would have to KNOW EXACTLY where to put the concentrated tip of the finger.