Most recent thing I have learned (guitar related) is to try picking fast runs using an alternating right hand thumb and forefinger - tricky for a while but very neat and versatile when you can master it. For the all time best example listen to Willie Walker play "South Carolina Rag" in 1930 (blind of course) at https://www.youtube.com/watch?v=oWGN178hkOY - amazing stuff. (There is also an alternate take which has different licks!).

I believe Mr M. Knopfler employs a similar approach when he plays electric guitar - no flatpick involved (he learned his trade playing acoustic blues with Steve Phillips in Leeds, as "The Duolian String Pickers", a little before my time there).

Regards - Tony