Some resources geared for the intermediate Python programmer.
- Hitchhiker’s Guide to Python, especially the section on Structuring your Project and Testing Your Code
- Dive Into Python 3 is a solid book for the intermediate programmer looking to deepen his or her skills. Especially check out the sections on Unit Testing and Refactoring. There's also the Python 2.x version.
- Refactoring is a classic. Yes, it's printed on dead trees and code samples are in Java. But the collective wisdom and many of the practical techniques remain invaluable. It's an eye-opener.