An education catalog exists on the XNA Game Studio website that was very helpful in teaching me many topics about basic game design and how to use XNA to its full potential. This library has recently been re-ported to MonoGame. The articles, tutorials, and samples are really worth a read through for anyone learning the framework.
They cover everything from Shaders to array best practices to managed code performance to a RPG framework.
Anyways, here is the ported samples: https://github.com/DDReaper/XNAGameStudio.