Here is how I solved this case.
I worked with pale green, teal, white, sand and deep charcoal. I worked mostly around a beach / water / nautical theme by adding in little elements suiting said theme. I also used striped paper that was pretty much the same as the swimming costume, some arrow chippies and I added some strips in my layering to resemble the little towel in the image.
Here are some more shots of this piece.