Watch the C Funky online guitar lesson by Larry Carlton from 335 Blues
When it comes to playing rhythm on a funky blues, muted parts with accents can fit the bill nicely. Heavy muting also gives a real percussive feel, where the pitch itself is sometimes barely audible.
We knew we were in C as this groove started, but there was no telling whether it was C minor or C major. As long as I didn't play the major 3rd (E) or the minor 3rd (Eb), I could play along without committing to major or minor.
Likewise, the funky double-stop parts played on the upper strings didn't commit to major or minor because they avoided the 3rd as well.
One approach for getting the feel just right is to intertwine your part with the bass so the two work like a rhythm unit.
I always like to start a part simply, with lots of space, and then gradually add to whatever motif I've established. For this part I first alternated with the bass player - almost like a question-and-answer thing - then I started dropping in little double-stop and single-note accents.
I find that when a jam is going badly, it's often because it's getting too cluttered. That's when I back up, take a breath, and play a sparse part that leaves enough room for the music to breathe and allow the listener to connect with that music.