Watch the Blues: Technique 6 online guitar lesson by Robbie Calvo from RhythmCraft
The chord voicing I've chosen for this technique lesson is perfect for arpeggiating through the entire 12 bar blues progression as it allows you to apply finger vibrato to the top note with your first finger. The top note just happens to be the root of the chord which helps us define the changes nicely. The chord, is quite simply a dominant 7th chord without a 5th degree and is voiced root, major 3rd, b7, root.
Check out my right hand picking approach to this and also feel free to expand upon the theme with your own ideas. Try finger picking the notes too.
Added some tremolo effects to this which gave it a swampier sound reminiscent of Creedence Clearwater Revival. Cool.