When you try to draw a dog in the paper, you actually translate the concept of a dog into an image, instead of using the actual image. Knowing how to draw things realistically is nothing more to learn how NOT to translate concepts into images.
Real artists don’t draw concepts, they draw the percepts. Inside their minds, they realize what they see is just a complex image of shadows, lights, shapes and colors instead of an abstract concept of an object derived from percepts, they draw the POINT OF VIEW.
Source: Drawing With the Right Side of the Brain, by Betty Edwards.
TD;DR: Instead of drawing “a dog”, you must learn to draw “a point of view in which there are shapes, colors, lights that resemble a dog.”