Start with the fabric provided to you. Do not dye or alter the base color of the fabric. Fold the fabric in half. This is to find the center.
Now that you have the center cut a slit just along the crease. This needs to be just big enough to slip over the head. You can cut a smaller slit in the center of the first one. That helps to give a little more room.
I used pins to mark where the seams would go.
Slip the dress off with pins still in place. Use a ruler or a straight edge to true up the seams. Use a straight stitch along marking lines.
If you are not going to use fringe, trim away the excess and then turn.
Slip the dress back on. Check the hem line. Hem can be straight or come to a point. Dresses should be knee length when the young woman's arms are raised straight over her head. This is also a good time to mark the neckline. Necklines can be scoop, V-neck, square or whatever you want. Nothing low cut.
Here are some examples:
Now that your dress is stitched together it is time to decorate. Dresses can be decorated with ribbons, beads, paints, feathers, sharpie, embroidered, etc.
Alternate method: Use a t-shirt as a guide. Fold fabric in half. Lay t-shirt on top. Use that as a guide to mark your seams.
Need some inspiration? Follow this link to see pics of dresses: