Watch the Modern Mixolydian online guitar lesson by Brad Carlton from Chord Studies: Modal Progressions Vol. 1
Quartal harmony applied to the 1st, 2nd and 3rd strings using the A Mixolydian mode can give us a nice modern sound. Especially that A7add4 chord. You can pull various chords out of the progression to create your own Mixolydian tune - just use your ear to determine when and where to use them, some can be more pleasant than others!