I am preparing system design interview recently, and want to share some of the resources that I find useful:

• System Design Primer
• HireInTech System Design
• InterviewBit System Design
• System Design Cheatsheet
• Grokking the System Design Interview

System Design High Level Approach:

• Scenario (Clarify/Features/QPS etc)
• Service (Application/Module etc)
• Storage (SQL/NoSQL/Schema etc)
• Scale (Sharding/Replication/Load Balancing/Caching/avoid single point of failure/CAP Theorem etc)

Good luck everyone!