well...its true that we can go the easy way by desaturating the photo from the coloured version and then playing around with the curves...but unless its a commercial project..where you have to convert like a few tens of photos...then dont....
for a more emotional and a more powerful feel, you must first try to shoot the subject in a way where its b&W friendly, identifying good textures or maybe even good contrasts....learn how to train your eye to see things in tonal values rather than be distracted by colours....
try playing around with the dodge and burn brush...i play with tat a lot..and most books i read...the black and white photographers prefer to make their photos darker than desired...cos it would have been the best of the b&W photo, and of course, be smart about that, not all photos are great that way...
personally, i like to put the exposure of the dodge and burn brush to 3%, and the brush size 200 (when my photo resolution is at 180 dpi ), should be quite comfortable to work with