Berceuse

I am finally delving into the romantic period. In this little piece, which is really an exercise, I explore the use of secondary subdominant chords, as well as relationships by thirds.

Very nice harmonies!  And the melody is charming as well.  Because you start with an 8th note and a 2nd beat that is then stressed by the inclusion of the left hand Eb it sounds like the 2nd beat is the downbeat in that measure.  At least I hear it that way, but then in the 2nd measure the stress is on the 1st beat so there it begins to sound like 6/8 proper while the measure before sounded like a kind of 5/8 with an anacrusis.  Why do you always modulate by a major third?  Eb major -> G major -> B major.  This is really short and would be nice if you now introduced some contrasting melodic material in the new key of B major.  Those are my thoughts.  Thanks for sharing!

@PeterthePapercomPoser

What you mention about the anacrusis and 5/8 at the beginning seems possible to me but it is complicating what is there. The point is that by delaying the E flat in the bass, you make the interval not a fifth with the Bb (which is a consonance but not as nice...) but a third  with the G. On the other hand it adds interest as it doesn't sound so square.
The fact of modulating by thirds is that this relationship of ascending major or minor thirds is common in romanticism, both modulating and following each other.
I did not conceive this as a "musical work" but as an exercise. I may continue it because I like the sound of it.

Thanks for your feedback.

How it is made (Spanish and English):  

https://komptools.blogspot.com/2023/10/acordes-subdominantes-secundarios.html