Overview
The double diamond method is one of the most common design methodologies. It uses a four-phase process to understand user problems and develop solutions: Discover, Define, Develop, and Deliver.
For each stage, you use either divergent thinking — considering anything and everything — or convergent thinking — thinking narrowly and focusing.
In discover, think diversely about the user, and accept any and every response from conversations.
In define, develop key areas that map onto the customer journey.
In develop, ideate profusely with various creative methods.
In deliver, refine the product specs so the user problems are truly being solved.
Every product manager should be familiar with the double diamond approach, as you're bound to encounter product teams who use it as a process cornerstone.