Cpp Coding Standards/Development Process
Guidelines for the Development Process
Advice not directly related to the code but to the development process more in general. Some of these are already implemented in OpenOffice.org development.
Automate and don't rely on manual procedures where possible.
A warning is (usually) an error.
Invest time on your interfaces. (Each class has one.) They are the most important thing to get right, everything else can be fixed later.
Provide regression tests.
Use a checked STL implementation.