With your lighter shade (25% Gray) apply your color from the waist to the hem, radiating in a in a sunburst pattern. You will notice that the overlapped will shade automatically making dark valleys and leaving light peaks. Make sure your strokes are crisp and sharp to show the stiffness of organza.
Step 2 - 3:
Following the same steps as the "Chiffon" demo, apply your darker shade (50% Gray) from the waist to the hem, leaving plenty of the lighter shade showing. Then apply your black revealing the chamise undergarment. Make sure your strokes are crisp and sharp.
Notice the difference between organza and chiffon? Organza has sharp straight angles. There should be no curves or roundness. The fabric also stands stiffly away from the body. Unlike chiffon, that hugs the bodies curves very similarly to a knit.