Octaves in G Major, No. 7, Op. 1 by Mauro Giuliani
From my PDF eBook: Ten Classical Etudes (Werner Guitar Editions)
Includes fingering, notation only & notation + TAB edition.
YouTube Video Performance and Lesson Link
Octaves are a real workout and great for the left hand position, finger independence, basic reach, stretches, shifts, and accuracy. Keep the left hand stable and let the fingers do all the moving. Do not change your hand position for every new octave shape. Play as legato as possible. Be careful to not injure yourself, take breaks and drink water.