A7: 1 3 5 b7 A C# E G
5 to 6 fret 3rd/G string (C b3 "non chord tone" to C# 3, A chord tone) then 5th fret B/2nd string (giving an E, thus the 5th) then 5th fret E/1st string (A which is root/tonic/1 whatever you want to call it!) then bending the b7 G at 8th fret B/2nd string up to the root note A.
"Real deal" players tend to approach a blues using Dom7 (or 9 etc) chords by playing the relevant arpeggios, Mixolydian and minor pentatonic scales all combined, weaving in and out of the underlying chord below.
Check out Robben Ford, Carl Verhyan and similar...