Originally Posted by Masuro
Consider buying a 'PV' (Pan Vision) filter, typically dark olive-green, which reduces all colours to tones quite convincingly and mimics the sensitivity of panchromatic B+W film (hence the name). SRB makes one: www.srbfilm.co.uk. You can carry it in your pocket and just look at different subjects. There's a picture of one in the free module on B+W in the Photo School at www.rogerandfrances.com. Alternatively, any strong filter will do but it will distort tonal relationships more -- I've even used orange-coloured cellophane sweet wrappers.
As Geoffrey Crawley said recently, you can often make a picture in B+W where none exists in colour, so I know what you mean.