WPF Best Practices

Accessibility Best Practices - http://msdn.microsoft.com/en-us/library/aa350483.aspx
Security - http://msdn.microsoft.com/en-us/library/aa970906.aspx
Localization - http://msdn.microsoft.com/en-us/library/ms788718.aspx
Performance - http://msdn.microsoft.com/en-us/library/aa970683.aspx

Getting Started on MSDN - http://msdn.microsoft.com/en-us/library/ms754130.aspx