When shooting in B&W, one must put texture, lines, contrast, and composition to good use. Without flashy colors to draw viewers in, the black-and-white photographer either masters the principles of composition or perishes. The things I have found useful when taking B&W photos are as follows:
Step 1: Enhancing Shadows
See pics. If you want to emphasize a shadow, shoot it in black and white. A lot of times, shadows are the entirety of a picture.
Step 2: Patterns and Lines.
Some other important things to look for are intricate patterns and lines, intersecting at crazy angles. Or just plain patterns and lines intersecting and normal angles. Either works and looks just as good. A lot of times, taking color photos of them looks good too!
Step 3: Textures
Textures are another important thing to note. Textures are everywhere. You can find them from the brick wall of your house to death valley in Arizona. Or a leaf to a cloud. A blade of grass. You get the "picture". Ba dum BUM! Aaanyway... Textures usually look every bit as good in color as in black and white.
Step 4: The Magic 7
I don't know why, but for some reason, pictures with lines and angles that make the number seven just look awesome!!! See picsif you don't believe me.