What are the most effective techniques for gathering and prioritizing user requirements during the initial phases of a project?

Hi Mark, 

it would be helpful if you can define what do you mean by users? Is it like users of a tech product or … in a more traditional consulting world it would be stakeholders (e.g., client counter-parts)?  

If the former, I think all the good product management tools and techniques are your go-to; but bear in mind that is not the bread and butter of management consulting. 

Best, 

Ariadna 

If this is about tech, I suggest starting with interviews. If it is something used by many people you should have a workshop for alignment (and to go more in-depth on a few topics and to solve any conflicts as well).