To me, the most challenging part of her costume would be making the gradient blue side cloth ^^. I succeeded on my second try, while the first being dyed to dark in color. Getting the color right wasn't tough, I think that challenge comes with how to hang the cloth to allow the dye to float down naturally. Should you not keep a tight watch on the cloth, a streak of blue line may just appear in between the gradient. Another challenge would be making Yuna's top costume, which is support only by two strings tied around the neck, along with a low cut on the back. I didn't apply any interfacing along the cutting of the costume, and things seem to work out ever better. The most satisfying part the outcome of her boots ^^ ~! The leather cloth I've found matches extremely well with the boots I've bought ^_^ ! And wonderfully, the cutting of the boots are exactly the same as Yuna's ^_^ !