Dave Celentano's book Secrets of Shred Guitar argues that "...the secrets of shred", include "sweep, alternate and tremolo picking; string skipping; multi-finger tapping; legato, [and] trills." The instructional book Guitar Shred includes exercises on "...Speed Building, Legato, Tapping, [and] Sweep Picking." The GuitarPlayer.com reviewer of the book Shred! claims that the book covers the "...techniques shredders need to know—sweep picking, tapping, legato playing, whammy bar abuse, speed riffing, [and] thrash chording" Shred guitarists also use two- or three-octave scale or mode, played ascending and descending at a fast tempo. This run or lick can be played by individually picking all, or a selection, of the notes, using techniques such as alternate picking, or economy picking. Alternatively, the lick can be played by multiple-picking notes (tremolo picking), or picking just the first or second note of a string followed by a rapid succession of hammer-ons and/or pull-offs (legato).
Sweep picking is used to play extremely rapid arpeggios across the fretboard (sometimes on all strings). The tapping technique is used to play rapid flourishes of notes or to play arpeggios or scalar patterns using pure legato with no picking. Various techniques are used to perform passages with wide intervals, and to create a flowing legato sound. Some performers make complex combinations of tapping and sweep picking.
Michael Angelo Batio