This piece is no 6 from Op 44 by Fernando Sor (1778-1839) and is currently a grade 3 exam piece for Trinity College of Music.
The piece will utilise your ability to play scales and arpeggios fluently. It consists only of single notes apart from the two chords making a perfect cadence at the end. Nevertheless you should be able to hear the implied harmonies as you play through the music. A good exercise is to work out these implied harmonies and play them as a simple chord accompaniment while you hum the melody line to yourself. This will help you bring out the harmonies more clearly when you play the piece.
The key of the music is G major, but from bar 9-12 it modulates to the relative minor key, E minor, starting with a B dominant 7th chord. The D#s that appear are raised leading notes in the key of the E minor. Bars 13-16 take us through the key of D major, again starting on the dominant 7th chord (an A dominant 7th this time). The C#s belong to the key of D major.
The remainder of the music is in the home key of G major once more, with the exception of another brief modulation to D major in bars 23-24.
Notice how the piece starts with an incomplete bar containing a single crotchet. This indicates that phrases will probably end on the second crotchet of the bar rather than at the end of a bar. When trying to work out the phrase structure of the music you can expect its other phrases to begin on the 3rd beat of the bar.
Look out for repeats of earlier sections, as this helps to make sense of the structure of the music. The repeats can be slightly different from the original statement. Look at the first 8 bars (from the very beginning of the piece up to the second beat of bar 8). Now compare this with the section starting on the 3rd beat of bar 24 through to the end of the piece. You'll see that the first four crotchets are turned into quavers played in octaves in the repeated section. A similar thing happens when bar 5 is repeated as bar 29: the original crotchets now have a third added above, making them into quavers.
Also look at the section that begins on the third beat of bar 16, then turn to the section starting on the third beat of bar 20 and you'll see that it's the same, only an octave higher. You might want to consider how this might influence your choice of dynamics (i.e playing loud and soft). Would you play the repeat at the same dynamic level, or would you want to play it louder or quieter?
I'll be adding an MP3 recording of this piece in the near future.