Well here is a helping hand.
- Always shoot in COLOUR. Yes colour. Convert to black and white in your image editing software afterwards. This will give you far more control over the large variety of tones in your image and each colour can be controlled seperately when converting to monochrome. There are also a number of specialised plug-ins that will help you achieve some amazing effects such as Topaz Black and White or Googles Niks' Silver Efex Pro
- If you want to see roughly what your image will look like in mono before you start shooting, then by all means set your camera's picture style to black and white or infrared etc just to give you an idea but DO NOT be tempted to use this fomat for your final image. Remember the camera will guess at the best tones etc. for your final black and white image, where as you, the photographer, want control using your editing software to achieve the best desired effect.
- Always shoot in RAW. More information = more final control!
Subjects that work well:-
Portraits / Reportage / Photojournalism / Street photography
Landscapes (especially those shot in moody weather with fabulous clouds). Winter snowy shots can be particularly good.
Interior / architectural shots where there are great angles and / or a variety of light sources
Solitary flowers, especially dying ones! (Curled dried petals can produce amazing shapes)
Subjects that are more difficult:-
Animals / nature shots in general
Large groups of flowers / flower beds and borders
Travel shots and landscapes with featureless plain blue skies. OK if you can import another sky perhaps? Sunsets (The colour is key here)!
Any scene in general where the colour defines the scene; such as the golden hues of autumn or the pale green shoots and unfurling leaves of spring.
Herewith a few examples from my images
Enjoy and experiment.