Getting Started with Ruby on Rails can be an exciting journey for beginners venturing into web development. Ruby on Rails, often simply referred to as RoR, is a powerful web application framework written in the Ruby programming language. It follows the convention over configuration principle, which allows developers to create applications faster and more efficiently. To kickstart your journey, you’ll first need to install Ruby and Rails on your local machine. This can be done easily with tools like rbenv or rvm to manage Ruby versions, followed by the installation of the Rails gem using the command gem install rails.

Once you have Ruby on Rails set up, it’s time to create your first application. Open your terminal and run the command rails new myapp to generate a new Rails project. This command will create a directory named 'myapp' containing all the necessary files and folders. Navigate into this directory using cd myapp and start your Rails server with rails server. Visit http://localhost:3000 in your web browser to see your application in action. Remember, the community around Ruby on Rails is vibrant and helpful, so don't hesitate to look for tutorials, documentation, and forums as you progress in developing your skills.

When developing Ruby on Rails applications, the right plugins can significantly enhance performance and functionality. Here are the Top 5 Plugins to Supercharge Your Ruby on Rails Applications:

1. Devise: This flexible authentication solution allows developers to add user authentication to their applications effortlessly.
2. ActiveAdmin: A great tool for creating elegant backends for your applications, ActiveAdmin makes managing data simple and user-friendly.
3. Paperclip: If your application requires file uploads, Paperclip is a fantastic plugin that simplifies file attachment management.
4. RailsAdmin: With RailsAdmin, you can quickly set up a backend interface for your application, thus speeding up the development process.
5. Pundit: For managing authorization, Pundit offers a clean and simple approach to user access control, making your application more secure.

When developing applications with Ruby on Rails, beginners often fall into several common traps that can hinder their progress and lead to less efficient code. One major mistake is neglecting to follow the Rails conventions. This framework offers a set of conventions that, when adhered to, can significantly speed up development and reduce complexity. For instance, failing to properly set up the project structure or ignoring the MVC (Model-View-Controller) architecture can lead to a tangled codebase. Always strive to keep your code organized and maintainable by working within the guidelines that Rails provides.

Another prevalent mistake is not taking advantage of the built-in testing frameworks that come with Rails. Many new developers skip this crucial step, leading to bugs and performance issues down the line. Implementing tests early in the development cycle can save a lot of headaches later, ensuring that your application runs smoothly as it scales. To avoid this pitfall, adopt a test-driven development (TDD) approach and continuously write tests for your features. Utilizing tools such as RSpec or Capybara can further enhance your testing practices and contribute to a more robust application.