Words need context
The same phrase can mean different things to different teams. A requirement that appears clear in a meeting may hide several incompatible expectations. Use actual working situations to understand what each participant means.
Explore the rules
Ask what happens in ordinary cases and at the edges of the process. Which information is needed, who makes the decision and what determines the next action? These details are often more useful than another abstract description.
Write for use
A requirements document should support design and evaluation. Keep the business purpose visible, explain the important terms and make assumptions explicit. Clarity is a practical delivery tool.