I talk to the people doing the work.
The audit starts with deep dive interviews, from department heads down to the frontline staff actually creating the value. No generic questionnaire. I write personalised questions for every person and keep adapting them as I learn how the business fits together. I ask what eats their day, what they redo, and where they sit waiting on someone else. Most leadership teams are genuinely surprised by what comes back, because the bottlenecks are almost never where they think they are.