Another way to make your blues solos sound magic is to use the mixolydian mode. This can expand your playing beyond the often used and predictable minor pentatonic scale. The mixolydian mode is a major scale with a flattened 7th note.
So while a G major scale uses the notes G A B C D E F# the mixolydian mode uses the notes G A B C D E F with the F being F natural and not F# as it is in the G major scale.
This makes the mixolydian mode a suitable scale to play over the dominant 7 chord which are used in the 12 bar blues. For example the notes of the G7 chord are G B D F which are part of the G mixolydian mode. So for a blues in G you have 3 chords and their corresponding modes which are:
G7 = G mixolydian = G A B C D E F
C7 = C mixolydian = C D E F G A Bb
D7 = D mixolydian = D E F# G A B C
While you can solo over the 12 bar blues using the main patterns (shown above) for each mode changing position for each chord can sound quite disjointed. To create a more cohesive and flowing solo it is better to be able to change between the 3 modes in the one position.
Here the 3 patterns for each mixolydian mode are outlined in the same (or overlapping) positions. Practice the patterns below to get used to them. Also observe the common notes between the 3 modes as they can help connecting one mode to another when the chords change in the 12 bar blues progression.
Check out the example solo below which uses all 3 modes.
Mixolydian Blues Solo | Download
You can see now that many of these notes overlap which can be handy as it means that they will fit however you want to label them. For example the B note is the major 3rd of the G7 chord and the 3rd note of the G mixolydian mode.
So with all this extra knowledge up your sleeve see how magical you can make your 12 bar blues guitar solos sound.