There is no such thing as a "skeleton key" technique. I've always kind of searched for that one technique that fit every type of song I played, but I just can't do it. To play Rush best, I have to do moveable anchor and rake. To play RHCP best, I have to mount my thumb on the pickup, strictly alternate, and use thumb over grip so I can pluck hard enough without hurting. To slap RHCP songs, I have to use vertical thumb. To slap Jamiroquia, I have to use horizontal thumb. All these different techniques... gah! It's kind of frustrating. It's not like guitar when you really only have to learn 4 different styles for 95% of songs: alternate picking, down stroke only, tapping, and sweeping. I can never find one thing that works in all the songs I play.
