XP consists of 12 main practices that cover different aspects of software development, such as planning, design, coding, testing, integration, and deployment. However, not all of them are equally essential or applicable to every project. Some XP practices are more fundamental and beneficial than others and can provide a solid foundation for your Agile process. These include user stories for concise and clear descriptions of user needs and goals as the basis for your requirements and planning, test-driven development to write automated tests before writing code and use them to guide design and implementation decisions, pair programming to share knowledge, improve quality, and increase productivity, continuous integration to integrate and test code frequently to detect and fix errors early, refactoring to improve code quality and maintainability by applying small changes that do not alter its functionality, and collective ownership to encourage everyone on the team to contribute to and take responsibility for any part of the code base.