Good conversations are key for understanding a domain; good tools are key to drive conversations toward actionable decisions.

Gojko is a fantastic trainer; product teams in companies of any size can get applicable knowledge.
He gives you the tools to improve facilitation techniques to help product teams clarify business needs, and then have a single source of truth that acts as living documentation.

Specification By Example is a hands-on workshop that will give you some techniques to use when defining requirements for a new or existing project, focusing on real examples.