The foundation of good interpretive work is a sound understanding of the geology.
It sounds trite, but you just cant get anywhere blundering around manipulating data without some idea of what to look for in the results.
I agree with the concept of systematically suppressing the things you arent interested in. The counterpart is systematically enhancing the features you are interested in, and that's where understanding the geology is crucial.
I think potential-fields interpretation is enriched greatly by the wide variety of technology in use. In many branches of geophysics, I see pretty much everyone doing the same thing. The fact that this isnt the case in gravity and magnetics may not comfort management, but it makes the business much more interesting.