In this chapter, you have learnt some best practices when designing an n-tier architecture. We explored some patterns, such as Repository, Unit of Work, and Factory in the data access layer, which provide many advantages for decoupling the dependencies, and how to use them in the business layer for database manipulation. We explored the benefits of keeping entities and other helper classes in the common layer so that they can be used throughout the layers. In the service layer, we developed a few controllers to show how the business managers can be injected and how logging and exception handling can be done. And finally, in the presentation layer, we configured Angular and designed a frontend framework to invoke HTTP services, display messages, and view models to carry data. In the next chapter, we will learn about implementing a Service Oriented Architecture using .NET Core.