Watch the Someday Baby online guitar lesson by Jeff McErlain from Essentials: Advanced Blues Rhythm
There are some really fun chord changes in this song that can be used in many other situations. The first thing I would do would be to learn the chords as standard barre chords stand apart. Familiarize yourself with the changes and the form. As you look at what I'm playing, you'll realize that I'm mainly playing smaller pieces of the larger chords. That's important to see as it makes memorizing and understanding where all this comes from all that much easier.
A good rhythmic figure to start on is playing beats two and four, this is called the backbeat. And as you can see, that's mainly what I'm doing on the first run through. It may seem very simple to do, and it kinda is, but keep in mind that simple is good! Remember you'll have someone most likely singing and or soloing over this progression. By playing on beats 2 and 4, you're guaranteed to stay in the groove and stay out of everybody's way.