Here is a rock practice track in the key of A. The chords are A, C, D and E – all power chords comprising the root and fifth. It is done at a slowish 100bpm, so you should have plenty of time to pick up what’s happening. See if you can work out which chords are where using your ear! The note G on the bottom string is used as a bend in between A chords and E chords – a standard rock and roll move!
Practice your improvising using the A minor pentatonic scale, with the addition of a B on the E chords!