As I stated before, I'm borrowing Johnny Winter's take on the Stones classic "Let it Bleed," one of my favorite cover tunes. I love Johnny's driving approach to this track, turning it into a heavy blues rocker. The riff is a variant on your basic boogie-woogie pattern but with a little more vibe and edge.
In the second half of the groove (the verse), we would normally want to bring it down a little bit to give the vocals some room and differentiate it from the chorus. A good rule of thumb is to be loud in the beginning for the riff, bring it down a bit for the verse, and slowly bring it up a bit and rock out for the chorus. Most rock 'n' roll tunes follow this dynamic pattern, which really makes a lot of sense once you think about it. It's also the hallmark of a good player and band when everyone takes full advantage of using dynamics in the song. Let me stress that this should be rehearsed! Getting used to incorporating dynamics in the band's repertoire takes time and often discussion about where the song should go. In improvisation, dynamics are just as important and the band needs to be listening to each other at all times. I can tell you from personal experience you cannot expect dynamics just to happen, so practice them with the band as well as on your own!