These are charming and vivacious dances, typical of Mozart's lighter instrumental works. They are characterized by their clear melodies and graceful rhythms, perfect for social dancing.
Focus on crisp articulation and maintaining a light, even touch throughout the rapid passagework.
6 German Dances (K.509) 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 6 German Dances (K.509) lasts about 2 minutes.
6 German Dances (K.509) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.