The first order of business was to make it smaller. To do this, I just laid a shirt that fits over the top and cut around it, and sewed up the sides.
I removed the pocket, very carefully so I didn't rip a hole in it. Not that I'm prone to doing that on knit fabric or anything. I cut the sleeves and excess from the bottom into 3" strips and used that for the ruffles on the front and neckline. After playing around with ruffle placement and picking the best layout, I sewed the ruffles down and hemmed the bottom of the shirt. And that was it!