Selecting colors - What's the best approach?

[tosime]

When you want to change colors for most objects you can navigate to a color
wheel made up of contiguous hexagonal shaped colors. I have often wondered
if there was a reason for the layout of the colors. For instance, should you
select colors along a particular row, diagonal or corresponding position in
the wheel? Can anyone point me to an article or reference which uses this
layout to show how to improve color selection?

Thanks in advance...Tony