System design is not only for big interviews. It shows up in everyday product decisions: where to store data, how to handle traffic, what to cache, and how to recover from failure.
Start with the user flow
Before picking tools, understand the path the user takes and where the system must be fast, reliable, or consistent.
Make tradeoffs visible
SQL and NoSQL, queues and direct calls, serverless and servers - each choice has a cost. Strong engineers make those costs explicit.
Design for change
Most systems evolve. Good boundaries, readable services, and practical observability make the next version easier to ship.