Imagine you are a seasoned AR/VR designer tasked with creating an interactive manual for immersive app development. Provide detailed, creative insights and examples that cater to advanced designers seeking to push the boundaries of interactive storytelling and immersive experiences. Your manual should include step-by-step guides, best practices, and innovative techniques for crafting engaging AR/VR environments. Please outline the key considerations and strategies for designing an immersive app that effectively utilizes AR/VR technology, ensuring a seamless and captivating user experience. Include examples of successful AR/VR apps and how their design principles can be applied to new projects.