Here's the tee I bought from Threadless to reconstruct. It's an XXL version of "Frida's Garden" by Dale Sattler. This is after removing the sleeves and the top shoulder seam
I'm using a BurdaStyle pattern as a base for my fitted tube dress, folding down the top of the pattern to the underarm line. I used a curved pattern ruler to grade my pattern down to the bottom of the tee hem to extend the length.
I added embellishing stitching lines to the design on the front, and also set the design off center. The top has a band of medium grey jersey knit to help hold the dress up, and the bottom has a dark grey jersey knit band for added interest (not seen in this photo).
The back has been fitted with a few pieces of elastic to improve the fit. The back half of the grey band has elastic to help hold the dress up and in place, and the base of the lower back has a piece of elastic that gathers slightly, helping to prevent too much slack. The bottom back of the hem is also slightly gathered along the jersey knit band, giving a hint of a ruffled effect, as well as shaping under the booty.
A detail shot of the stitching embellishment and original design.