The progression: 12 bars
The 12-bar blues uses three chords: the I, IV and V. In A these are A7, D7 and E7. Each line below is four bars.
Many bands already play the IV in bar 2 (the 'quick change'). In bar 12 you play the V as a lead-in to a new round: the turnaround.
| A7 | A7 | A7 | A7 | | D7 | D7 | A7 | A7 | | E7 | D7 | A7 | E7 |
Step 1: A minor pentatonic at fret 5
Start with the A minor pentatonic (A C D E G) in the familiar box: index finger at fret 5, root on the low E string. This makes almost everything sound 'bluesy' over all three chords.
Add the blue note E♭ (G string fret 8 or A string fret 6) as a passing note, not as a note to land on.
Step 2: mix in some major
The C from the minor pentatonic clashes with the C♯ of the A7 chord. That's actually the blues sound. Bend the C slightly up towards C♯, or alternate between C and C♯.
Over the A7 chord you can also use A major pentatonic (A B C♯ E F♯), as B.B. King and Freddie King often do.
Step 3: target chord tones
When the chord changes, play a note that belongs to the new chord. Over D7: the F♯ (third) or the C (♭7, already in your pentatonic). Over E7: the G♯ (third) or the B (fifth).
This way the listener hears the chord changes in your solo, even without backing.
Step 4: call and response
Play a short motif in the first two bars, then repeat or answer it in the next two. Leave space: silence is just as important as notes in the blues.
End a round on the root note A, or play a turnaround lick in bars 11–12 that resolves to E.
Practice tip
Put on an A blues backing track (search for 'A blues backing track'). First play just the root notes A, D and E along with the chord changes, then add licks.
