Remember blues rhythm guitar isn't only about chords! Learn box shuffles in all their many variations-Buddy Guy's playing on Jr. Wells' "Hoodoo Man Blues" CD is a primer-learn 'em all, especially "Snatch It Back and Hold It"! Learn boogaloo patterns-Louanne Bartons version of "Tee Na Nee Na Nu" is a good start. Rumba blues like the T-Birds ""Walkin' To My Baby" or the song "Early In The Morning". Learn "Baby, Scratch My Back" Riff based backup guitar is a lot of fun, and most importantly, leaves SPACE! Don't clutter all the available space in the sonic palate.
I've got the sickness...