When shooting black and white photography using natural light, you should let the situation dictate the look and feel of the photo. So don't set out and try to shoot a high contrast shot unless you find a good opportunity with the right lighting. Try shooting on an overcast day.

If the subject matter and intended message of the photo are more important than the eye candy of vivid or eclectic colors, then black and white is the way to go.

What is contrast? Contrast is the range of brightness, from lightest to darkest, in an image. A high-contrast image will have very bright highlights and very dark shadows. Sometimes an image's highlights may be almost pure white, or the shadows may be almost pure black: high contrast.