Very good question. I try to "see" in BW while shooting such. You look for different things like tonal contrast etc , while shooting in colour you tend to look for different sets. I wish we had a viewfinder that would let us see in monochrome, in a cheaper camera than Leica-monochrome that is . With a bit of practice shooting for BW becomes much easier.A question for all those who've posted here. Did you visualize your picture to be in B/W before shooting or was it just the PP that looked better in monochrome for a particular photograph and it eventually resulted in a B/W picture?