Schubert's song 'An die Laute' D. 905, when performed on piano, often takes on the character of a delicate nocturne or romance. It is known for its gentle, flowing accompaniment and expressive, lyrical melody.
The key is to achieve a singing tone and a light, almost ethereal touch in the accompaniment.
An die Laute (D.905) is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 4.
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 An die Laute (D.905) lasts about 2 minutes.
An die Laute (D.905) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.