Watch the Texas Shuffle online guitar lesson by David Hamburger from Blues Alchemy

If you can keep your rhythm guitar playing interesting to you, it will make things more interesting to everyone else playing and listening, too. Try and think of what you're doing chorus by chorus, and build up the variations gradually. I've stolen a lot of ideas from listening to horn sections, and you can too - check out the Joe Williams/Count Basie version of "Every Day I Have the Blues" for a stellar example of a tune built on nothing but a series of unfolding riffs.