Let's draft the pattern for this asymmetric top.
It features a one sleeve neckline, high-low hem and gathers on the opposite side seam creating a sort of ruffle.
You can sew it in any lightweight fabric, as this shirting cotton.
Start from a basic block with darts and sleeve. First, mirror front and back.
You can learn our method for drafting perfectly made to measure basic blocks (contoured ones, and the ones with wearing ease) and for fitting them in our basic blocks course/module 1. You will learn in depth also how to manipulate darts, add volumes and a lot of pattern transformations that will take your pattern making skills to a higher level.