List and explain techniques for eliciting requirements

What will be an ideal response?

Interview is most flexible and direct tool for eliciting requirements. It also more prone to misunderstanding and failure than any other technique. Early interviews in the requirements gathering process have a broad scope, while the later ones are defined by more focus on detail. Interviews fall between two extremes: structured, where we can control the flow, and focused, where we must go deeper with the flow. Since interviews are a finite and expensive resource, they must be planned carefully in advance to derive maximum benefit.
Questionnaires are the second choice for requirements elicitation and the first choice for requirements verification. The structure of questionnaires as elicitation tools are generally the same as in interviews, but the flow is inflexible. As a verification tool, questionnaires are the most traceable.
Elicitation workshops are the most powerful, but also the most expensive tool for requirements elicitation. Since they are very expensive, you must select participants carefully and help them to help the workshop.
Field trips and observation provide valuable requirements where workflow is rich in action and interaction. But you must be aware that the value of observing a workflow also depends on the goal of the observation.
Models can be used to verify requirements. These models need not be formal blueprints for the construction of the system, but can be any drawing or word chart that the stakeholders can understand. Mock-ups are one such modeling technique; they are approximations of the system's user interface to elicit comments and requirements.