How can I diagnose the specific cause of an "npm run build error"?

Start by carefully examining the error message in the console output. It often provides clues about the failing file, line number, and type of error. Check your build script (`package.json`) for typos or incorrect commands. Try running the build command with the `--verbose` flag (e.g., `npm run build --verbose`) for more detailed output. Use debugging tools within your build process if available.