I just made one . Honestly, I had a large scrap of fabric, it went around the bottom of the t-shirt about one and a half times. I held the t-shirt and fabric up to my daughter, and eye-balled the length to see where it would fall on her legs. I folded over the bottom edge to create a hem (straight stitching) and at the top put my machine on straight stitch with the widest length and sewed all the way around, then about 1/4 inch under, did that again. I had left the thread with long (about 3 inches) ends on each end and did not secure when I did the sewing (meaning no forwards and backwards sewing to put it simply) then pulled the threads gently and "pushed" the material to the center to create "gathered" look. I then pinned to bottom of t-shirt (I had cut off about 4 inches of t-shirt to make length work.) They were turned inside out and then I sewed these together. I did secure the stitching that step. It is by no means perfect, but it is complete. I love it. some site on here has a quote along those lines. I used an old t shirt, and material that I had no idea what to do with, so even if it messed up horribly, I would not be upset. Like I said , I just love it. I just bought several t-shirts, and tanks at Target and
Walmart, and "soft book" patterns. I plan on cutting out the square of the book, and apply ing it to t shirt, and then doing coordinating material for bottom of dress. Walmart has these books in Nemo, Pooh, Princess and Ariel. I am very excited!