Clarifying the actual question is a big part of it. Sometimes clients ask for x but they really want to know the answer to y.
Assembling data is a big part of it too but you have to think conceptually about what that means. What’s the right data? Where is it found? Do I have to go and create it or does it already exist? What are the limitations? Are there other considerations beyond quantitative data - eg consumer behavior, regulatory constraints, capacity constraints? If relevant, what might be a competitor response and how to prepare for that?
On this board, we do “consulting” every day for the kid/parent who says “help me choose a school for engineering” or “Harvard is my dream school, how do I get in”. We ask questions to clarify the objective / goal - what kind of engineering, why engineering, what about Harvard and ca those qualities be found elsewhere. We ask questions to establish / clarify the parameters - my family can only afford $x, I don’t want to travel more than x distance, I have a special disability that needs to be considered, etc. We ask questions to clarify the inputs, what is changeable, what isn’t. We help find sources of data and explain the limitations - here are the rankings, but understand that you have to squint at them, etc. We brainstorm alternate solutions/options that the person hadn’t thought of - have you thought about schools a, b and c in addition to Harvard. This process is the process of consulting.