My fabric was about 23 inches wide and 27 inches long.
6) This will be the casing for your elastic. You need to sew around the bottom, but leave a small opening (a inch or two) to add the elastic in. Make sure you backstitch to keep this from raveling.
7) Now we make the little hoop for the ribbon to go through. This step is not required. You might not want to loop the ribbon. It takes more time and if you want a "true" simple dress you can just skip this part and add in your elastic.
8) Hoop. Cut a small rectangle of fabric. Sorry, this isn't very specific. Fold it in half. Iron.
9) Fold each side to the middle to meet the crease. Like so. Now sew it down.
10) Now here is a kind of tricky part. I dont know if there is an easier way to do this. Probably. Let me know if you are aware of one. Find the middle of the dress. Just fold in half. Iron.
11) Take your little folded, fabric rectangle and put in the the middle of the iron crease. Pick out the seam there and slide the fabric in.
12) Okay. Now fold the other end over to the front side and tuck it in. Pin and sew that bad boy down.13) Slip your elastic into the little hole you left open (Adding on a safety pin helps) and work it through. Be sure to watch the other end and not let it slip into the other side to be lost forever.
14) When you've made it all the way through, sew both ends of elastic together. Sew up the opening. Put your dress on your little model. This part is pretty tricky.
15) Cut a piece of ribbon big enough to fit around her neck. Tie. Watch her flaunt her new dress.