Read the following chapters from The Pragmatic Programmer (in our library):

• Software Entropy
• The Evils of Duplication
• Orthogonality
• Decoupling and the Law of Demeter
• Evil Wizards

Read the following chapters from Clean Code (in our library):

• Chapter 1: Clean Code
• Chapter 2: Meaningful Names
• Chapter 3: Functions
• Chapter 4: Comments
• Chapter 5: Formatting
• Chapter 8: Boundaries
• Chapter 10: Classes
• Chapter 12: Emergence
• Chapter 17: Smells and Heuristics

Also read:

• Keep It DRY, Shy, and Tell the Other Guy
• GRASP (object-oriented design)
• Single Responsibility Principle

Read the following chapters from our book Growing Rails Application in Practice:

• Dealing with fat models
• Extracting service objects

Discuss with your mentor what you took away from each topic.