If you want to draw a portrait or still life, or render a perspective of a building, for example, there are a number of different techniques you can use. Which drawing technique you decide to use depends on how you want your drawing to look. Some techniques are used to make your drawings appear more realistic, while others are suited for cartoon-like illustrations.
You can add dimension and texture to a drawing using the cross-hatching shading technique. Cross-hatch is done by making crossing lines instead of just filling an area with a darker shade. The technique itself is easy to do, but you still need to take care where you add the shading and how much. The cross-hatching should be more dense in areas with the deepest shadow, and become more sparse up in the areas where the light is hitting. Use this technique if you want your drawings to be more cartoon-like and less realistic.
Circulism is a way of adding shadow and texture with a more realistic outcome. Create a series of small, tight swirls with a pencil and make them more dense to create a deeper shadow. You can also use a blending stump or your finger and a tissue to soften the swirls or circles. Applying various degrees of pressure with your pencil will also produce a lighter or darker shade. Use this technique when you want to give the subject a more realistic but textured look.
Blurring and Softening
For surfaces that need a very soft or smooth look to them, like human skin or glass, there are a few techniques and tools you can use to achieve this. After you add the shading to the area, use a soft cloth called a "chamois" to soften the visible pencil lines. Cover the tip of your finger with the chamois and make small, circular motions on the area of the drawing. You can also use a piece of tissue this way. For small areas that need more precise softening, you can use a blending stump, which is just a tightly rolled strip of paper.
Drawing contour lines is a way to show dimension, shape and even shadow without doing any shading. Of course, you won't get a realistic result, but the outcome is a very detailed drawing. To show the shape of a vase, you would draw the outline and then draw some lines somewhere along the inside to show where it curves. You would also focus on the stems of the flowers inside the vase and draw curved lines around them to make them appear round. Contour lines are also used to emphasise details and texture.