Go beyond looking for many bright, harmonizing colors. Consider the drab background with the brightly-colored subject. This splash of color highlights and draws attention to the subject.
The roles are reversed in the second group of photos, where the "splash of color" is instead a lack of color. Color normally leaps to the foreground, but when there is a lot of color, it becomes the background as the eye is drawn instead to what is different. For another example of this role reversal see the Negative Space page.
See also how expert photgraphers portray Splash
Of Color, Splash
Of Color 2007, Beginner
Splash Of Color 2007.
Reversed-Role Splash of Color, a splash of no color surrounded by color.
Boy Scout Troop 174, Yorktown, NY. Scouting Photography Pages at http://troop174.info