I have just finished my second string quartet in d minor. Compared to the G major quartet posted on my page here, I think it is a big leap forward in a great many ways. It is held within the Classical style, with a first movement in sonata form, a second slow movement in ABA form and a final movement in rondo form.
I have taken some inspiration from the writings of Joseph Haydn ending the first movement in the major tonic, and using only two part writing in the first theme of the final movement, much like Haydn does in his minuet of the "Fifths" quartet (although mine isn't a canon).
The quartet is written with the limitation of only using the first position on each instrument, which I think I managed to do.
If you want to take a listen you can find the music here:
String quartet in d minor:
The score can be found here