Watch the Steady Bass 12-Bar Blues online guitar lesson by TrueFire from Play Acoustic Guitar 1: Quick-Start for Beginners

Here's a 12-bar blues with the steady bass. The switching is the hardest part at first, but as you keep working on the solid bass line, it becomes easier to move it around. Take as much time as you need on this to make sure you have it down and can keep the steady bass line going.