OK, well when a friend asks me to help with a kimono set, they normally think you just need the kimono and obi. So here is a list of what a girl needs for a average kimono ensemble.
1. Kimono (duh!)
5. Obi makura
6. Obi ita
7. Juban with haneri
8. Hadajuban (you can get away with not wearing this if your juban is synthetic)
9. Up to 5 koshi himo
10. 2 datejime
11. Eri Shin
For me Tabi and Geta/Zori are optional as quite often I wear boots.
This is what my average kimono ensemble entails. Start collecting!