Watch the Chuck Berry: Super Chuck online guitar lesson by Chris Buono from 40 Day Rhythm SWAT Camp
It's always fun to add a few twists to the classic Chuck Berry rhythm riff (ex. 1), which you can play straight or with a swing feel. I discovered my first variation trying to decode Jerry Reed's "Tupelo Mississippi Flash." I never got that tune exactly right, but I've learned many good licks trying to assimilate something I couldn't quite hear. On a country gig, whenever the singer calls a number I've never heard, I smile and play Ex. 2. I inevitably get looks of admiration for "nailing" what was on the record.
Examples 3 and 4 are alternate blues-shuffle figures. The former is fairly simple and works well supporting vocals. The latter really swings and could push a soloist over the top.