I've talked with a lot of people on the project and collected a lot of notes, but there's got to be a better way. What's the most effective way to get at the most important requirements for this project?
How should you begin eliciting the requirements? At one extreme, you might decide on a 100-percent hands-on approach: just sit down and write the requirements for the business stakeholders, and ask for their signatures. Or, at the other extreme, you could go totally hands-off and ask the stakeholders wide-open questions like, "What do you want?"
Extreme strategies like these are rarely successful. Handing the stakeholders a blank page is likely to elicit more irritation than valid results, and leave you still wondering what truly matters the most. But presuming to know everything and writing the requirements yourself is equally unlikely to get you an accurate requirements list.
A common, effective approach is to start with what you know, portray it as "draft" or a "strawman", and give the business stakeholders something to react to.
Start at the level of the business need. What is the reason for this project overall, and what are the most critical goals? You don't want to have open discussions about all the things that could be done, outside the context of what really matters the most. If you already know that the business needs certain types of functionality, for example, or if you're aware of specific gaps or pain points, start with those. In your early "discussion draft" you might also include some non-functional requirements (e.g., corporate or departmental standards) that you can dig out of existing documents.
Include educated guesses about the requirements, based on your understanding of the business need, and open the conversation by asking for the interviewees' reactions. This approach will help get things moving in the right direction, and elicit critical information faster and more effectively than either a blank slate or know-it-all approach.
See our guideline on Software Requirements Capture for more tips.