Find a picture of the dog you would like to draw. Do not attempt to draw from a live subject, since a live dog will likely not sit still for poses. The picture should be large, high resolution and detailed.
Draw the outline of the dog. Look back and forth between the photograph and the drawing to make the outline. These pencil marks should be made lightly, since you will very likely cover up these lines when you draw the fur on the dog over the outline. Consider using a pencil with a hard graphite core -- a 4H pencil or higher. Hard graphite pencils naturally make lighter lines than softer graphite pencils.
Draw the details of the dog, including eyes, nose and mouth. Most dog eyes are large and dark, without much of the whites showing. Most dog noses look like an upside-down triangle, black or brown in color. In addition, some dog mouths appear to be "smiling" -- they are curved upward at the back as the dog pants. Study the shape of the dog's eyes, nose and mouth in order to draw the most realistic facial features possible. If there are other large details on the dog -- such as the outline of a prominent spot in the fur -- add these as well.
Shade the parts of the dog that are medium or dark toned, like dark areas of fur and the eyes. Shade lightly at first and darken the areas in the drawing until the drawing matches the photograph. Use a softer graphite pencil -- 4B or softer -- for shading.
Draw tufts of fur in the areas where the fur is light enough that it does not warrant shading. Tufts of fur may be indicated by small groups of curved lines, moving in the direction of the fur on the dog's body.