The melody of Only Once In My Life by Agustin Lara runs 212 notes across 35 bars, 2:43 long in Ab at 100 beats per minute. The tab sits almost entirely in the first two frets, one note at a time — no chords to barre and no strumming pattern to keep up with. A piano backing track plays the chords and bass underneath, so the line you are learning sounds like the record even at half speed.
Prefer to strum and sing it instead? Only Once In My Life chords and lyrics.