For fun, but also educational (from Guitar World’s 2012 “Dear Guitar Hero”)…
Slash: There are a lot of players whose technical knowledge is far superior to mine - guys that have a good grasp of music theory and apply it to their playing all the time. I can’t do that… [I] know how to play major, minor and pentatonic scales all the way up the neck, but that’s about as complicated as it gets.
Yngwie: I don’t have any “strategies” [for building speed and improving fret-hand ability]… You can’t ‘build’ speed; you play it until you have it perfect. There are no shortcuts and no tricks. The saying ‘practice makes perfect’ is truthful.
Petrucci: [on improving speed] There are a few different ways. First is the tried-and-true metronome method… The second method is to simply play the lick over and over at varying speeds, without ever stopping. The third way is to break a lick into tiny fragments and master each at a high speed until you have the whole thing down pat.
Gilbert: [on alternate picking issues] I would guess that you need to work on your fretting hand. Most people have a problem coordinating both hands. In general, when I see people whose picking sounds wrong, it’s not because their picking isn’t fast enough but because their fretting hand isn’t fast enough… I didn’t do any significant fast picking until I’d been playing for about eight years. And by that time my fretting hand could perform Van Halen-style ascending sixes, like you hear on “Spanish Fly”
George Lynch: [on improving the fretting hand] One exercise that I used to do is work my fretting hand without using my pinkie and ring finger. Try that, and also work on hammer-ons and pull-offs. In fact, I’d suggest trying to take the right hand out of the mix completely.