People and objects placed in your sketches help to give scale to the image.
In your sketchbook, draw a line that is about six inches long (blue line in image below). Divide the line in eight parts. Create a ellipse to represent the head.
Create a front view and a side view of a human figure as shown below using lines divided into eight parts. For more information you can visit Human Anatomy Fundamentals.
Using the 8-module proportions shown above, fill a sheet with approximately 1-inch high stick figures in various positions and engaged in different actions.
Figures could be: sitting, climbing stairs, running, laying, doing yoga poses, hanging, swinging, crouching,
Repeat exercises 2, but show the outlines of the figures.
In her book titled Sketching for Architecture and Interior Design, Stephanie Travis tells us:
In perspective sketches the eye level of all average adult figures on the same ground plane will align. People who are closer to the viewer are larger, and people who are farther away are smaller, but their eye level remains the same. (Travis 72)
Using a fine-tipped pen draw a horizontal line that represents the horizon. Using a medium-tipped pen locate human figures at different scales along the horizon line.