Quick, concise introduction to playing legato style guitar like Joe Satriani or Steve Vai. Legato = Smooth. Pick the first note on each string and sound all other notes using hammer-on's and pull-off's.
Ready to develop some left hand endurance? Many great guitar players like Allan Holdsworth, Steve Vai, and my personal favorite, Joe Satriani, have made great use of this predominantly left-hand technique to create lines that really flow. Here's a step by step breakdown of legato-style guitar:
1) Cover the frets - This technique typically employs 3 notes-per-string. Try holding down all 3 frets on one string at the same time with three different fingers. If you can do this, the hard part is finished! Now play a G Major Scale by picking the first note, then by hammering-on the second note while still holding the first note. Then hammer-on the third and final note on the string while still holding the first two fretted notes. Follow this procedure with each string. (Ex.1)
2) Pinky Strength - Time to put that pinky to work! Spend a significant amount of time holding down two notes and hammering on and pulling off with the pinky.
3) Go backwards - When performing the pull-off's, make sure all three notes are in place before you begin playing. Make sure the pull-off is an actual pull down on the string. Pull down slightly on the string, then flick your finger away. Simply lifting the finger off the string will not produce the desired sound.
Pick the first note of each new string, but if you really want it smooth, begin each string change with a hammer-on and avoid picking entirely (this only really works for the descent)! For a musical example, check out Greg Howe's use of this on "Button Up" (1:02) from the album "Introspection".
Change it up - Try the following example in the style of Joe Satriani. (Ex. 2) Once you get comfortable with this technique, you can let it fly every which way without too much thought (as long as you know your scales)!
Go SLOW - Like everything in music, GO SLOW. Do not try playing too fast straight out of the gates. Playing too fast is the quickest path to... FAILURE! You do not need to be a speed shredder tomorrow, or the next day. You just need to get a little better today. You need to be a super shredder in 3-5 years! Think long-term.
Now quit wasting time on the Internet and GO PRACTICE! If you've already recognized your need for an effective coach to take your playing from blah to YAH!, check out the best Fort Worth guitar lessons available and don't go another day without progressing on the guitar!