Here is some graphic designs which show good contrast elements.
Source: http://www.mojo.com.ro/blog/
The first one is associated with interior design, a black and white large scale image. Its character might represent fingers. Like this, to recognize what it is, a contact of black and white works well in here. Each color pops up another different color, which makes its figure and flow easy to be figured out. Also, a contrast of scale works here. If it is the picture of only wall, it can be recognized as a small image. But there is a bad, a human sized object, to show how large it is.
Source: http://www.goodisdead.com/
Next example is a simple graphic design, a image of cheese.
The cheese makes a good contrast of black background, which cause strong expression of cheese itself. Also, with using different tone/value of yellow, we can notice it is a cheese. If it is just only one value of yellow, we might not recognize it. Lighter and darker yellow shows different surfaces. The gradation of color from white to yellow, shows a hole. There might be a contrast of shape. The small circle on larger cheese let us think it is a mark a mouse bit into a cheese. If the circle was larger size like a half size of a cheese, we do not think so.
Subsequently, here is a bad example of contrast, I think.
It represents lines of airplanes. The contrast of lines and empty spaces does not have a good balance, too much lines to see. But, Good thing in this design is the contrast of color. Since its background is blue and green, those red lines pop up well, besides the black dots which indicates stops of airplanes pop up on the red background.