• Ask questions to the interviewer for CLARIFICATION: Since the questions are purposefully vague, it is advised to ask relevant questions to the interviewer to ENSURE that both you and the interviewer are on the same page. Asking questions also shows that you care about the customer requirements.
• Gather the requirements: List all the features that are REQUIRED, what are the common problems and system PERFORMANCE parameters that are expected by the system to handle. This step helps the interviewer to see how well you plan, expect problems and come up with solutions to each of them. Every choice matters while designing a system. For every choice, at least one pros and cons of the system needs to be listed.
• Come up with a DESIGN: Come up with a high-level design and low-level design solutions for each of the requirements decided. Discuss the pros and cons of the design. Also, discuss how they are beneficial to the business.

The primary objective of system design interviews is to evaluate how well a developer can plan, prioritize, evaluate various options to choose the best possible solution for a given problem.