I took in Doc Watson's guitar workshop at the Berkeley Folk Festival in 1964. Two clues from the Doctor himself:--

Fellow asks: "How did you learn to flatpick that fast and smooth?"
The Doctor: "Well, I practice scales about a half an hour every day."

(Sixty some-odd aspiring folk guitarists suck in a breath of air and look horrified)

Fellow asks: "Can you tell us what you do when you are finger-picking?"
The Doctor: "I don't really know how to describe it. It's kind of an arpeggio." (big grin) "'Course, I'm not suppossed to know words like that."

(Sixty some-odd aspiring folk guitarists writhe and moan in great distress)

I guess it's like the old gag about "How can I get to Carnagie Hall?"

Don Firth