Basically I've been playing guitar for over 10 years. I'm 28. Some things I've allways had trouble with is hammer ons, pull offs, and super fast scales. This solution might seem simple too many but it wasnt to me. You see i figured the secret to speed was a lack of wasted movement and being fluid like a jazz or classic guitarist. I can play pretty fast and have some licks, but it sounds spanishy and psychedelic, not rock n roll. However, i was practicing the other day I was just like " fuck it, maybe i should play really hard" and I did. I really strained my hands and banged my fingers against the frets. The result was I played really fast and got that rock n roll soul sound i loved. I guess this is something that comes from blues and I've seen guys do it but it never occurred to me to play like that. Anyway I'm going to be doing some weight exercises to increase my grip strength and wrist/tendon strength from now on. I hope this helps somebody.