Another technique I find useful is document analysis, where I review existing documentation, such as process maps, user guides, and system specifications, to gain a deeper understanding of the current state and identify areas for improvement.
To ensure that I have a complete understanding of the business needs, I also like to create use cases or user stories, which help to illustrate how the system should behave from the end-user's perspective. This not only helps me to identify any gaps in the requirements but also ensures that the proposed solution meets the needs of the users.
Finally, I find that iterative validation and feedback are essential to ensure that the requirements are accurate and complete. By regularly reviewing the requirements with stakeholders and incorporating their feedback, I can ensure that the final solution aligns with the business needs and expectations.