Listening to players like Mississippi John Hurt, Reverend Gary Davis, and John Fahey will get your ear accustomed to fingerpicking blues. In this lesson, we'll apply the techniques they're known for to a 12-bar blues, but you can also use them to play ragtime, early jazz, and folk.
Let's start with a basic picking pattern on an open E chord (Example 1). You'll use your thumb to play the notes on the bottom three strings and your fingers to play the top strings. I recommend using a thumbpick—it helps put more oomph in your oom-pah. Begin by playing just the bass strings. This is called an alternating bass because you alternate between two strings, in this case the E and D strings. Next, add the melody notes, using your middle finger to play the B string and your ring finger to play the high E string. Notice that the bass strings are always struck on the beat, but that the melody notes can be played on the beat or the offbeat, which provides a little syncopation.
Example 2 is a slight variation on this pattern, substituting the G string for the B string. Use your index finger for the notes on the G string and your ring finger for those high notes again.