Thin slicing the brain.

Creates a whole lot of data!  Nature reports on 'Whole human brain mapped in 3D' by Helen Shen, June 20, 2013.  The atlas was created from 7400 slices of a human brain, each thinner than a human hair, and nicknamed 'BigBrain'.  Here's the quick summary:

The brain is comprised of a heterogeneous network of neurons of different sizes and with shapes that vary from triangular to round, packed more or less tightly in different areas. BigBrain reveals variations in neuronal distribution in the layers of the cerebral cortex and across brain regions — differences that are thought to relate to distinct functional units.

Given that we are still working on a model for a simple worm with 302 neurons, there's obviously a long way to go with the full human brain.  But you gotta start somewhere, and I'm sure that having an accurate map will help (now just drawn from one example, but as they do more they will get an idea of the individual differences that are possible - I'll bet they can be pretty significant).