Use a tape measure to find the distance between the graduate's shoulders, the arm length from shoulder to wrist, and the gown length from shoulder to mid-calf. Record all three measurements.
Iron the fabric and spread it out on the floor. Fold it in half and mark a rectangle with seamstress chalk. Add 1 inch to the gown length measurement to determine the length of the rectangle and divide the measurement between the shoulders by 4 to determine the rectangle's width. Make one long side of the rectangle the folded edge of the fabric. Cut out the rectangle.
Line up the rectangle on the remaining portion of fabric, with the folded edges together. Trace the rectangle and cut out another rectangle. Unfold both rectangles.
Find the center of a wide edge of one rectangle and cut the fabric directly though the center, dividing it in two long strips. Reattach the strips by sewing the zipper between them. Sew the zipper's edges to the inside of the fabric. Align the zipper so there are at least 2 inches between one end of the zipper and one end of the fabric to allow for the collar hem. Use straight pins to attach both fabric rectangles together so the gown is inside out.
Mark a rectangle in the fabric using the arm measurement as your length and 20 inches as the width. Cut out and cut along the fold line to separate the sleeves.
Stitch the side seams of the gown's body together, leaving 12 inches loose at the top for the sleeve attachments and shoulder seams. Try the vest-style garment on the graduate to mark the notches for the neck hole and collar. Cut the notches and fold the fabric down. Stitch the collar seam along the inside of the gown and cut away excess fabric.
Fold one wide end of each sleeve rectangle 1 inch in and pin the 1-inch fold to the inside of the fabric. Hemstitch the cuff and remove the pins. Fold the sleeve rectangles lengthwise and pin them together so the sleeves are inside out. Stitch along the seam and remove the pins.
Pin the unhemmed end of the sleeve to each armhole in the gown and stitch it together. Remove the pins and stitch the shoulder seams from the end of the sleeve to the collar opening. Turn the gown right side out and give it to the graduate to try on for fit.
Measure the circumference of the graduate's head with a tape measure. Add 1 inch and cut a strip of black cardboard to that length, 4 inches wide.
Wrap the cardboard strip around the graduate's head and paperclip the ends together to create a snug fit. Remove the strip from the head and join the cardboard strip ends with rubber cement.
Cut 1-inch slits along one edge of the circle, approximately 2 inches apart. Fold the slits in toward the center of the circle. Wrap the uncut section of the circle in black fabric and attach with the fabric with hot glue.
Cut a 10-inch cardboard square and a 10-inch square of quilt batting. Cut a 12-inch section of black fabric.
Center the batting square on the underside of the black fabric and pin it in place. Turn the black fabric right side up and locate the exact center of the square. Sew a black fabric button in the center of the cap.
Turn the cap button-side-down and remove the pins. Place the cardboard square on the quilt batting square and pull the excess black fabric tightly over the cardboard, being careful not to create any creases or folds in the cap. Staple the fabric to the cardboard. Cut off any excess fabric tails.
Place hot glue on the folded segments of the cardboard ring and attach the square to the cap base. Wind the tassel around the center button to complete the graduation cap.