Ruby on Rails, often abbreviated as Rails, is an open-source web application framework built on the Ruby programming language. It enables developers to create dynamic and database-backed web applications with ease. By following the Convention over Configuration principle, Rails reduces the number of decisions developers need to make, accelerating the development process. This framework encourages the use of RESTful architecture, which helps in creating scalable and maintainable applications by adhering to standard web conventions.

For beginners, getting started with Ruby on Rails can seem daunting, but it is essential to grasp some fundamental concepts to make the learning curve easier. Familiarize yourself with key features such as MVC (Model-View-Controller), routing, and migrations. Additionally, utilizing tools like Bundler for dependency management and ActiveRecord for database interactions will enhance your productivity. By understanding these basics, you'll pave the way to building your first web application with Rails, setting a solid foundation for more advanced topics in the future.

Building scalable Rails applications requires a clear understanding of best practices that enhance performance and maintainability. Following best practices can lead to cleaner code and improved application performance. Here are the top 10 best practices that every Rails developer should consider:

1. Use database indexing wisely to speed up query performance.
2. Implement caching strategies to reduce load times and database queries.
3. Adopt background jobs for long-running tasks to keep the web request cycle fast.
4. Optimize your assets by using a content delivery network (CDN).
5. Monitor application performance using tools like New Relic or Skylight.
6. Follow RESTful conventions to ensure your application's architecture is predictable.
7. Employ Service Objects to keep your controllers skinny and logic clean.
8. Utilize feature toggles to enable/disable features without deploying new code.
9. Write tests to catch issues early and maintain code quality.
10. Scale vertically and horizontally as your user base grows to manage increasing loads effectively.

As you embark on your development journey with Ruby on Rails, it's essential to be aware of the common Rails pitfalls that can derail your progress. One prevalent issue is neglecting to follow the convention over configuration principle, which can lead to unnecessarily complex code and confusion within your application. Additionally, not leveraging the powerful Active Record features may result in inefficient database queries, hampering your application's performance.

Another pitfall to avoid is inadequate testing. Failing to implement automated tests can cause significant issues as your application grows; bugs that might have been caught early can turn into major headaches down the line. Remember to integrate testing into your development process from the start. Finally, being unaware of the Rails security best practices can leave your application vulnerable to attacks. Ensuring that you stay updated on security measures is crucial in safeguarding your project from potential threats.