The sleeves have short-row shaping at the start to give the bell shape, and then the sleevehead is gathered into the armhole to add the ruffled effect.
Both sleeves and body have a folded hem (one of my all-time favourite design features in a garment).
The fronts and back also have little pleat details. And the cardigan is finished with ribbed ties and a knitted-on ribbed edging.
Amanda and Lily are such a lovely team for photographer and model. Thank you both again!