Regardless of the development process used, the project doesn't exist without some form of requirements. The first step in even agile processing is to determine what the requirements of at least the current timebox are.
While researching guided interviews and use case scenarios, it became clear that they were just two steps in the over all process of requirements gathering, so I lumped them together on this page. I'll be documenting the best practices I've found in my readings of several texts, and in at least two cases pointing to further readings recommended by those authors which I have yet to get my hands on.
Commercializing Great Products with Design for Six Sigma.
While this text is primarily concerned with the generation of software for commercial sale/use, the sections on preparing and conducting Guided Interviews are very appropriate.
The interview guide should include a single sentence purpose statement. The book gives several sample templates for the structure of these sentences but they generally breakdown into:
To Verb for gaining information Customer Focus in order to Business Focus
A simple example of this from my own recent projects would be:
To discover the methods and standard practices that the MRC uses to provide AV and technical support to events in order to help design a system which will automate and track equipment/inventory as well as provide additional billing capabilities.