Idea Mapping: Idea Map #11 - Considered Colour by Steve
In her book, "Idea Mapping", Jamie Nast explains the value of deciding the purpose of your map before you start to draw it.
You may have seen on Jamie's blog, Jamie and I discussing different approaches to mind maps. The approach you take may be driven by your own personal style or, in particular, the needs of the moment and the purpose you want to achieve with the map.
Jamie has been kind enough to use two of my examples to demonstrate at least two takes on this subject.
See also Idea Map #10 - Fast 'n Furious from Steve