I started with a plain yellow tshirt from Hobby Lobby (kids Large so it would be more like a baby tee) and I cut the sleeves to be shorter, cut the neck to have a scoop like a shirt I had around, and cut the hem off the bottom of the shirt.
Then I took strips of white jersey from another tee I cut up (the one I made into a shrug that I haven't worn yet or posted pictures of yet...to do list.) and sewed them under the sleeves, neck, and bottom (1 on each sleeve, two rows on the neckline, and three rows on the bottom.)
I stretched them a little to encourage curling, especially after it's washed! I like it! :)