Watch the Combining Positions: 2 online guitar lesson by Andy Aledort from Progressive Blues Power
Just a quick note on the chord progression I'm playing over: while in the key of E, we start on the four chord, A7, move back to the one, E7, back to the four and then to the five, B7. A turnback to the one, E7, is followed by the four, A7 and then Bbdim7 (diminished seven), and the progression ends with a nice I-VI-II-V (one-six-two-five) progression, E7-C#7-F#7-B7, which avails great opportunity for soloing freedom.
I begin the solo in fifth position E minor pentatonic, which straddles the line between this scale and both A minor and A major pentatonic. Over the next two bars of E7, I switch to descending doublestops, thirds apart, that move down the G and B strings. When returning to A7, I move all the way down to open position, using a great variety of open strings, and then move quickly back up the fretboard to play in seventh position over B7. The primary objective is to move freely and musically between positions, so try the same approach in the creation of your own solos over this progression.