Begin by making 12 consecutive sections across your paper. Next, find 12 colored pencils to match the 12 color spectrum in this order: red-violet, red, red-orange, orange, yellow-orange, yellow, yellow-green, green, blue-green, blue, blue-violet, violet. Try out your colored pencils on paper to check their true hue before shading in.
Now for an exercise in the relationship of value to color, local color and complementary combination.
First, make a black and and white achromatic drawing.
Now find the local color of your subject. The local color refers to the color of the subject in noontime white, natural light.
Make another black and white drawing adding the local color to make a monochromatic (one color plus black and white) drawing.
Next, a drawing using only the local color. In this case; yellow-green, to match the tennis ball.
Now, using just the complement. The complement is the color directly opposite of your first color on the color wheel. Red-violet is opposite yellow-green.
Finally, make a drawing using the 2 colors together.