Theodore Oesten's "3 Grandes Valses brillantes" Op.54 are popular Romantic-era salon pieces known for their virtuosic brilliance and catchy melodies. They would be characterized by their dazzling runs, clear waltz rhythms, and appealing harmonic progressions.
Focus on maintaining a clear, lilting waltz rhythm while executing rapid decorative passages.
3 Grandes Valses brillantes (Op.54) is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7.
You should be comfortable at Henle level 5 — meaning you can already play level 4–5 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
3 Grandes Valses brillantes (Op.54) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.