An important exercise I used for strength building is hammer-on pull-offs. I start out at very first string 1st fret and hammer towards the 2nd, then pull off and away to the principal. I keep on moving up until I get the 6th string. After I reach the 6th string I move over a fret, and afterwards it go down again to two. I repeat the process until my fingers get sick. While doing this it is best to use a...