I once mentored a junior developer struggling with backend concepts like database optimization and error handling. To help them improve, I started with pair programming sessions, tackling real-world tasks together. For example, we worked on optimizing slow SQL queries by analyzing execution plans and implementing indexing. I also broke down complex concepts into smaller, manageable parts. For instance, when covering error handling, we focused on applying try-catch patterns to specific API scenarios. During code reviews, I provided constructive feedback by explaining the "why" behind suggested changes, like restructuring overloaded endpoints to follow separation of concerns. I also encouraged independent exploration by sharing resources and discussing their findings in follow-up sessions. Within three months, the developer advanced from writing basic CRUD operations to creating scalable API endpoints and efficient queries. They gained confidence and began contributing valuable optimization ideas to the team, which was incredibly rewarding to see.