Play like the Allman Brothers and Neil Young with Flatted III, VI, and VII Chords
If you’re working on a song that uses the I, IV, and V, try substituting the bVII for the V to give the progression a different feel.
In general, you can use the bVII to add zing to a progression otherwise made up of diatonic chords. For instance, the Allman Brothers’ “Ramblin’ Man” uses a I–bVII–I in the beginning of the chorus (“Lord, I was born a ramblin’ man”) to make that line stand out in an otherwise standard country/folk progression with the diatonic I, IV, V, and vi chords. Neil Young’s “After the Gold Rush” has the same set of chords and accentuates the bVII to add to the song’s mysterious mood.
Example 2 uses the bVII (an F chord in the key of G) in conjunction with the diatonic I, vi, and V. In measure 2, play a hammer-on from the open third string to the second fret to accentuate the change to the bVII.
Excerpted from Songwriting Basics for Guitarists: Blues/Rock Changes