Using perspective in our artwork helps us create "believable" scenery. The farther away an object is, the smaller it appears. We also create perspective by using "vanishing points" and rulers. See the website below for a step by step tutorial:
2 Point Perspective Drawing Lesson
Here is another website that is great for experimenting with perspective. Click a scene and add houses, trees, people and other objects.
Click on image to make it larger.