Here is a practice track that works with a blues aesthetic. There are two chords, E7 for four bars, then A7 for four bars. For a straight ahead approach use the E major scale with a flat 7 (also called E Myxolydian, or A Major) over the E7, and an A major scale with a flat 7 (also called A Myxolydian or D Major) over the A7. For a more blues oriented treatment, use the E minor pentatonic scale, bending up to the major thirds of each chord.
Here’s the practice track:
For bass players, here it is without a bass line: