Watch the Blues: Technique 7 online guitar lesson by Robbie Calvo from RhythmCraft
You've probably realized by now that I am giving you a tool kit of rhythmic and harmonic variations to broaden your value as a guitarist, regardless of genre. If you have a handle on these techniques and can transpose those ideas to other keys, your musical universe will open up and you'll be able to choose the right part for the gig by just listening to the arrangement.
Using major 6th chords over our 12 bar blues progression will give you the sound of the big band era and rockabilly styles. The major 6th voicing I have chosen for this can be used over the entire progression by locating the root of each of the chord changes.
There is a really cool move that I use over the "I" chord where I move down chromatically through E6 - Eb6 - D6.
We can break the D6 chord down to see that it's chord tones give us three of the notes found in an E9 chord. b7 (D),9th (F#) 5th (B). Which means the D6 will still work anywhere in the chart the E7 is present. It sounds really nice too.
You will want to be very careful when sliding this voicing as it can be very tricky to maintain the shape and hit the notes in the upper register of your guitar.
You can use a pick to accent these chords, or for a softer jazzier sound, you may want to try using the side of your thumb or the back of your fingers.