A great skill to have is the ability to use any of your fingers with the same efficiency. To work on finger strength, first use a clean setting on your amp. Start at the first fret, and hammer on with your index finger once on every string - make sure you can hear the hammer on! Go up all the strings from bottom to top, and then repeat with your middle finger. Once again hammer on the first fret - this time using the middle finger - going up the strings until you get to the top string. Repeat with your index finger and pinky. Again make sure you can hear the note you're hammering on! AND NO DISTORTION - that's cheating. Repeat the hammering process going up all of the frets, and withing weeks, you'll notice a dramatic difference in your ability to hammer on, bend, and overall you wiill notice that playing riffs soloing is much easier. I would also suggest practicing barre chord changes, including changing barre chords over different strings. Don't FRET (ha I'm so funny), every time you sit down (or stand up) with the guitar you get a little better - this will just help you practice the skills needed for playing rapid licks and solos.
"As long as I'm satisfied with my work, I'm not too concerned with what any critics think. Our type of music will never be a critical favorite, but when I can stand on a stage and see a lot of smiling faces in the crowd, it makes it all worthwhile."
- Randy Rhoads - Resting in Peace since March 19, 1982