To make a dress from a pillowcase, cut off the closed end, make the armholes, add elastic neck straps, and line the armholes with bias tape. The supplies you need include a pillowcase, scissors, a sewing machine and bias tape. You also need a measuring tape.
Cut off the closed end of the pillowcase, and fold it in half lengthwise with the cut end at the top and the fold on the left. Starting at the top-right corner, measure 4 inches down the fabric, and place a straight pin at that location. Place another pin on the top edge of the pillowcase, 2 inches from the right edge. Cut off the upper-right corner of the folded pillowcase, using the pins as a guide. Cut through all layers of the fabric, and discard the scraps.
Remove the pins, and trim the armholes so they resemble the letter J. Unfold the pillowcase, and turn it inside out. Lay the pillowcase on a flat surface with the armholes at the top. Fold down the top edge of the fabric to make a 3/8-inch channel, and pin it in place. Repeat on the back side.
Stitch across the pins, remove them, and run a 6-inch strip of 1/4-inch elastic ribbon through each channel. Fold two 32-inch pieces of bias tape in half lengthwise, pin them around the armholes, and sew them in place. Trim the thread, and turn the dress right-side out.