Here are the steps:
1. Gather your materials. You will need t shirts, jersey, scissors, a zipper, and a handy dandy sewing machine.
2. So my grey t shirt had a pocket on it, so I removed it with a seam ripper. Then cut the neckline and sleeves off of your t shirt.
3. Next take the large body section of your t shirt and fold it in half. Cut through both sides of fabric, creating a trapezoid shape. Make sure the wider end is the original hem of the t shirt, so you don't have to rehem it later.
4. Cut one of the large body pieces in half, leaving you with two back pieces, and one front piece. Cut out a strip of fabric (mine is blue) for the waist that is about 2-3 inches tall, and as wide as the front part. (I trimmed 2-3 inches off the top of the front piece, so when the blue is sewn to it, it will be the same length as the back pieces.) Next cut out two long pieces the same height as your front blue piece. Make sure these strips are long enough to wrap around your body and tie into a nice bow in the back.
5. Use a zig zag stitch with jersey material to let it stretch afterwards. Now sew the front blue strip to the top of your front grey piece.
6. Now we are going to make a sandwich. Take your entire front piece ( blue and grey sewn together), right side up and put it as the bread. Make the filling with one end of a strip, and the other piece of bread is one of your back grey pieces right side down. Pin and repeat with the other side. (Make sure the angled outside edges (of the grey) are lined up, so when it lays flat it is symmetrical and lines up correctly.)
7. Sew the two sides together, so you have one nice big piece, with the blue tie ends free. I didn't hem my waist ties because jersey is awesome and doesn't fray.
8. Now pin and sew the top part of your dress onto the body. After that sew the entire back seam together if it is stretchy enough, or install a zipper into the top part. I used a zipper because the 90's top had no stretch to it.