Producer Ceàn Chaffin, film editors Kirk Baxter and Angus Wall, casting director Laray Mayfield, to name few, are among David Fincher's close guard. Having such a solid network over the years probably allow you to build a recognizable style which eventually becomes your trademark. That's why you can see now a 'David Fincher' film as featured in Dragon Tattoo's trailer. Whether in arts or in business, it's all about working as a team and being interrelated. And Fincher masters that more than any director.
These professionals seem to share a characteristic which is precision. Jeff Cronenweth has an eye for it and Steve Zaillian admits he is precise too.
Read the two papers as you'll probably learn more about Fincher through his crew's own words than from his (notwithstanding Fincher Fanatic's landmark interview of course).
Jeff Cronenweth's profile on ICG Magazine here
Steven Zaillian's interview here