I've been playing mandolin for a few years and discovered the importance of pick angles while improving my tremolo. I realized that you cannot just keep the pick in the same orientation all the time so, nerd that I am, I started thinking about each stroke as a vector in six dimensional space (position and orientation in 3D). The trick for me is to simplify that to the point where I get the results I need.

Most of the material I saw online just had some basic recipes to improve right hand technique, there are very few systematic and rigorous explanations. I think that's where a good teacher can make a massive difference.

On the other hand I also have first-hand experience with nature vs. nurture - I play music with my wife and kids and I'm clearly the least talented although everyone brings something unique to the family band.

As always, the truth is a combination x * talent + y * nurture so I'm glad to see the discussion turning that direction.