Another technique for drawing folds and drapery is to use contrast and texture to create interest and variety. You can use contrast in terms of value, color, and shape to show the difference between light and shadow, warm and cool, and smooth and rough. For example, you can use darker values and cooler colors for the shadows, and lighter values and warmer colors for the highlights. You can also use contrast in terms of shape to show the difference between straight and curved, sharp and soft, and large and small. For example, you can use straight lines and sharp angles for stiff fabrics, and curved lines and soft edges for fluid fabrics. You can also use texture to show the difference between smooth and rough, shiny and matte, and plain and patterned. For example, you can use smooth and even strokes for silk, and rough and irregular strokes for wool. You can also use dots, dashes, and hatching for patterns, such as stripes, checks, and plaids. By using contrast and texture, you'll create more depth and diversity in your sketches.