Use a good rubric
During a Product Manager interview, the interviewer is trying to understand your skills at developing new or extending existing products. They want to understand what is in your head, and the best way to make sure you communicate everything thoroughly with shared understanding is by using a framework.
The Universal Questions rubric is a great one to answer questions that are like:
- Product design questions: How would you design a phone for blind people?
- Product improvement questions: How would you improve YouTube?
The Four Critical Risks rubric is good for exploring whether a product concept/idea is going to work or not.