Think away the color
Black and white photography is a bit of an odd way to describe this type of photography. A black and white photo often contains mainly grey tones. This is why black and white photos are often called monochrome photos too.
Black and white photos give you their information by using luminance variations, not by showing variations in color. Your thoughts are not distracted by the colors and therefore the attention goes to subject, composition and lighting.
Not every subject is suited for a black and white photo and it isn’t always easy to ‘see in black and white’. There are, however, things you can pay attention to when looking for good subjects for your black and white photos. Subjects with lots of contrast will be more suited by the large variations in luminance. The right light is important; light that’s coming from an angle will make textures stand out. Light coming for only one direction will produce big differences in light and shadow…
Experienced black and white photographers are often able to think away the color in a scene. They imagine the scene in black and white. To do this, you’ll need a lot of practice, but it’s possible for anyone to learn. If you have a hard time trying to see in black and white you can always just take a black and white shot and view it the camera display. If you’re not using RAW, retake the shoot in color to be able to perform you’re own conversion instead of relying on the standard black and white conversion.
~Elja Trum from his article Black and White Photography; The World Without Color