For the Skittle it's all about emphasizing the top half and balancing the bottom half.
The cut shows of the slender waist, broadens the shoulders and covers the arms.
Puffed sleeves broadens the shoulders to balance the big thighs, and the bold print draw the attention upwards.
Knotted top draw attention upwards and shows of waist. A-line skirt is very forgiving on a heavy bottom half.