Watch the Barefoot in Rio online guitar lesson by Peppino D'Agostino from Acoustic Poetica
I think that one of the interesting aspects of this composition is the shifting to 3 different keys, which will expand your knowledge of chords, modulation and harmonization. In addition you'll be using a lot of bar positions, which will strengthen your left hand. The melody in the first 16 bars is played on the 1st and 2nd strings. On measure 9 the Db position is quite a challenge for the left hand. You really have to take advantage of the last D open string on measure 8 to form the chord "in the air" in order to reach it on time. Always pay close attention to the chord diagrams above the staff and to the left hand fingering suggested. On measure 10, the top Ab note (on the 2nd string-9th fret) is played with the index as you hold the notes of the Db maj7th chord. This is quite difficult at first so you have to practice this passage many times. Unfortunately you don't have any open string that would help the transition into the Gb maj7th on measure 11. Practice slowly at first, paying attention to have a clear and precise sound and then later worry about the speed of this particular passage. On measure 24 pay attention to the l.h. index finger sliding from the D# to the E on the 2nd string as you hold both the A and the C# on the 1st and 3rd string respectively. On measure 27 notice that you don't want to play the F7 by fretting the entire chord immediately but you want to build it up step by step. The chord change between Fmi to Bb7 on measures 33 and 34 requires a lot of l.h. muscle power. Pay attention to the triplet played with the index finger on measures 39 and 40. Measures 41 and 42 are particularly difficult for the left hand because of the fast chromatic descending scale. I suggest you use the fingering recommended on the music staff.