Leo Brouwer Etude 1 is excellent for developing strength and control. Particularly for the right hand which the study targets.
It is a rhythmic study providing the melody in the bass strings and the accompaniment on the open strings. The term cantado el bajo in the score literally means the singing the bass. A useful strategy is to isolate the bass line melody and become familiar with this before adding the rhythmic component.
The study has two goals
The first is to bring out the melody with the right hand by using a rest stroke with the thumb (p) on the bass strings and a free stroke with the i-m fingers.
The second is to achieve the dynamic contrasts. Etude No.1 moves from mf in the first bar to pp in the third bar to f in bar 5. The piece crescendos from bar 12, reaching its climatic moment in bar 15 - marcato emphasizes the need to perform these notes staccato and ff at an increased volume. While a ritardando is not indicated, many players interpret it as such. The morendo (dying) in the last bar is often played higher up on the guitar bridge to accent the effect of dying away.
Here's an excellent rendition by Alex Altamirano.