Gambini's work is an educational study that serves as an expressive character piece. It blends technical utility with a Romantic harmonic language intended for student development.
Balance the moving arpeggiated figures with a clear and distinct melodic voice.
Comparable difficulty and character — good candidates for what to learn next.
Andante en forme d'étude (Op.46) is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 5.
You should be comfortable at Henle level 4 — meaning you can already play level 3–4 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Andante en forme d'étude (Op.46) lasts about 4 minutes.
Andante en forme d'étude (Op.46) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include 'O sole mio by Eduardo Di Capua, Belle of the Ball by Leroy Anderson, Broadway Melody by Nacio Herb Brown — see the full similar-pieces list on this page.