Written by Stanley Myers, "Cavatina" rates as one of the most beautiful songs ever recorded. Its lush harmonies are worth studying; I'd like to offer my rendition here.
The song is in the key of E. I usually play it on the guitar in the fourth position, barring the fourth fret with my index finger and then grabbing the C-shaped chord. This formation then sounds the E major chord, with the major third (G#) in the bass.
Now, you may choose to strum the chords, or to arpeggiate them (meaning, to pluck the strings one by one). Or the combination of both approaches. It's all a matter of personal taste.
The way I hear the harmonic movement in this song, it starts with E major and moves into E major 7. Others seem to hear it as moving into G# minor rather than E major 7. The difference is rather slight, but nevertheless E major 7 sounds better to my ears. You voice that chord by grabbing the E major in the fourth position (as described above) and then simply lifting your middle finger off the fifth fret.
From E major 7 the progression goes to A major (in the fifth position), then three frets down to F# minor (grab it on the second fret). You may choose to stay on the F# minor for the entire bar, or to switch to B11 on the second half of the bar. Try both options, see what sounds better to you, and then stick to it.
Next move to B7, voiced on the second fret. Jump back to E major on the fourth fret, then E major 7 (same formation you've started with).
Now, switch gears to playing A major 7 on the fourth fret. Second half of the bar is F# minor, then G major 7 on the second fret, then C major 7 using open third, second and first string.
Close the phrase by playing B11 using open second and first strings, while fretting the second fret on the third string and fourth fret on the fourth string, followed by B7 on the second fret, and finally go to the open E major chord.
The above concludes the part A. Go back to the top, play part A again.
Now switch to part B. It starts with C# minor 7, played on the fourth fret. You then move to F#7 on the second fret, hop up to B major fretted on the seventh fret, then to B major 7 fretted on the sixth fret. Go to A major on the fifth fret, then up to B7 on the seventh fret, then back to E major on the fourth fret, followed by E major 7 on the fourth fret.
Finish off by playing A major 7 on the fourth fret, going down to F# minor on the second fret, then G major 7 on the second fret, then C major 7 using open strings, B11, B7 on the second fret, and finally finish off by playing open E major chord.