Watch the Gimme Some More: Rhythm 2 online guitar lesson by Andy Aledort from Jam Night Vol. 3
A technique used commonly for blues-style rhythm guitar is the incorporation of trills between the minor and major third. Here, I utilize that approach for throughout the entire example: over the initial C, Bb and F chords, the low root notes are sounded on the sixth string and fretted by wrapping the thumb over the top of the fretboard, with an index finger barre across the D and G strings at the same fret as the thumb used to sound the flatted seventh and minor third of each chord. the middle finger is then used to sound the trills--quick hammer-ons and pull-offs--up to the major third of each chord, found one fret higher than the index finger on the G string. For variation, I move away from the trills on the F chord and instead play a more melodic riff on the G and B strings.