When handling and displaying data grids and tables in a desktop application, it is important to follow certain best practices. These include considering usability and user experience, optimizing performance, providing advanced sorting and filtering options, implementing pagination, taking care of data validation and error handling, and offering customizable display options. Additionally, it is crucial to ensure responsiveness and scalability, use appropriate design patterns and libraries, and consider accessibility requirements. Following these best practices will help create a desktop application with efficient and user-friendly data grid and table functionality.