If you are looking for the technique of speed guitar or fast guitar or fast picking (you name it), and if you are the big fan of John Petrucci of Dream Theater, check the following reviews you will learn how to play speed guitar with accuracy.
First, watch the following video of how john petrucci teaches how to build speed guitar with accuracy:
Next, observe this video to learn alternate picking in building speed guitar skill:
My review on John Petrucci’s Speed Guitar Technique with Accuracy, and Alternate picking
John Petrucci learned how to play fast by observing how other guitarists played guitar especially fast/speed guitar. He mentioned that he got the influence from the guitarist of Van Halen, Eddie Van Halen. Eddie certainly implemented the combination of picking technique and Legato.
Some of my friends and my guitar teachers said that it is impossible to play fast guitar or speed guitar only using picking all the time, that is, to pick every single note. However, in fact, I saw some guitarists did that (picking every note for playing fast). Of course, the key to picking fast is accuracy. You need to play slow first in order to build accuracy. You finger, your hand, and your nerves must adjust with the timing, movement, and the distance of each fret of the guitar. John Petrucci did do fast or speed picking for every note. Beginners usually do fast picking, but there is no balance between the number of picking with the number of each note to be picked. For example, the were to play 4 notes fast, they would pick 5 until 6 times up and down. This is because they just pick up and down fast without paying attention to how many notes they want to pick. This problem is certainly of accuracy.
Legato, which many people consider that as pull off and hammer on technique, looks rather simple than picking every note because it is only the left hand working on it. The right hand only picks at the first and then Legato does the rest. Many beginners use Legato because they cannot play picking every note. Picking every note fast requires balance between left and right hand. I, myself, did Legato more than picking every note in order to trick my listener / the audience who were watching me playing fast guitar so that they say “wow”, although actually I did not do that great.
Combination of Picking and Legato. John Petrucci suggested using the combination of both. He called that Alternate Picking. That means sometime you pick, sometime you pull off. This combination is great when you want to play fast / speed guitar. The weakness of picking every note is that the sound is not really good compared to Legato. Many guitarists agreed that legato produced better / sweeter sound than does Picking every note. However, doing Legato all the time is surely boring. Combining them should give you easiness and awesomeness!