Agile development relies on feedback loops to continuously improve the development process. Short iterations and frequent delivery of working software allows customers to provide early and regular feedback to identify issues and ensure the project stays aligned with their needs. Feedback also comes from testing and following principles like rapid feedback and short releases where developers seek feedback quickly after each change and deliver new versions frequently to speed up the feedback cycle. The goal is to detect and address problems as early as possible through an empirical process of making changes, learning from the results, and evolving the process.