Well, more stickers, for starters!
From what I can make out of the pictures, you're already using three stickers: one pocket sticker over the torso, another on the back, and a large square sticker under those two wrapping around the hips. I like the way these stickers are arranged; the pocket stickers help define her figure and the large square sticker is placed high enough from the bottom to expose a strip of the underlying pattern, creating a border. Very clever.
The problem now is that this leaves large expanses of flat texture around the torso and lower body flaps. If my calculations are correct, you should have one sticker slot left on the robe. It'd be easier if you had at least one more extra sticker slot, since that would allow you to take care of the the upper and lower body separately. However, that's not the case, so, , you'll either have to choose between the two or find a way to address both areas with one sticker, assuming you don't change anything else in the current design. The good news is that you can choose any sticker you want. A large sticker (one of the ones at the bottom of the list) over the entire body could be a potential solution, but it's ultimately your choice.