Gathering user feedback during the GUI design process is crucial to create a user-friendly and effective interface. Here are some methods to collect user feedback:

1. Surveys and questionnaires: Distribute online or offline surveys to collect users' opinions, preferences, and expectations.

2. User interviews: Conduct in-depth interviews with potential users to gain insight into their needs and behaviors.

3. Usability testing: Observe users interacting with prototypes or early versions of the GUI, gathering feedback on usability and user experience.

4. Focus groups: Organize group discussions with users to collect feedback, identify patterns, and prioritize features.

5. Heuristic evaluation: Expert review of the GUI against established usability principles and guidelines.

6. Contextual inquiry: Observe users in their natural environment to understand their workflows, challenges, and needs.

7. Paper prototyping: Test paper-based prototypes with users to gather early feedback on layout, navigation, and functionality.

8. Online feedback tools: Utilize tools like user testing platforms, feedback software, or analytics tools to collect data and feedback.

9. A/B testing: Compare different versions of the GUI to determine which design elements resonate best with users.

10. Continuous iteration: Refine the design based on user feedback, testing, and analysis, and repeat the process until the GUI meets user needs.

By incorporating these methods into your GUI design process, you'll be able to gather valuable user feedback, iterate on your design, and create a user-centered interface.