Watch the 1959 online guitar lesson by Jeff Scheetz from 50 Blues Rock Rhythms You MUST Know
Here is a cool riff that can be played either with a little 'grit' on your sound, or played really clean and more 'funk' like. The slides from a half step below give it that blues sound. Try to keep the strings you are not playing muted. You can do this as a complete 12 bar, or just jam on the main riff in A for a funky kind of groove.