Shading techniques are methods used in art to create the illusion of depth and dimension on a flat surface. Common techniques include hatching, where parallel lines are drawn closely together, and cross-hatching, which involves overlapping lines in different directions. These methods help to depict light and shadow, enhancing the three-dimensional appearance of objects. Another popular technique is blending, which smooths out transitions between light and dark areas, often using tools like tortillons or fingers. Stippling, the use of dots to create texture and shading, is also effective. Each technique can be combined to achieve various artistic effects and styles.