You can visit the
Maya Learning Channel for a primer on how to use Maya's Render Setup system. Topics include:
Introduction to Render Setup
Setting up your first Render Layer
Matting and Cutting out objects from a Render Pass using Overrides
Generating fast first pixels with Local Overrides
Templating and Sharing Render Setups
Pre-lighting multiple shots using Overrides
Shader Overrides, shot optimization, and wrap-up