Black and White Photography

I have been trying lately to take some black and white pictures.. but most of them turned out grey (no subject or color really stand out in the picture, no bright white or dark black. Would you have any tips for me (any tips you may have for BW photography would be much appreciated). Could we get nice black and white pictures directly from the camera (I have a nikon D80). Sorry if my question seem very basic... i am still in the learning process... a! thanks! Julie