This document discusses techniques for improving code testability and maintainability. It recommends: 1. Applying SOLID principles like the single responsibility principle and dependency injection to reduce coupling and improve cohesion. 2. Avoiding direct static method calls and singleton patterns in favor of dependency injection as it allows dependencies to be mocked/stubbed for testing. 3. Following the law of Demeter to avoid excessive coupling between classes. 4. Using factories instead of singletons to allow injecting fakes/mocks for testing. Testing first and listening to tests results in more maintainable code.