Ensure proper handling of environment files by following these practices: (1) Add actual environment files (`.env`, `.env.local`, etc.) to `.gitignore` to prevent sensitive data from being committed, (2) Include example environment files (`.env.example`) in version control to help other developers understand required configuration, and (3) Add clear documentation in example files explaining how to use them. Example `.gitignore` entry: ``` # Environment files .env .env.local .env.*.local ``` Example `.env.example` with documentation: ``` # Copy this file as `.env.local` and fill in these values from your service console VITE_FIREBASE_API_KEY= VITE_FIREBASE_AUTH_DOMAIN= ``` This approach ensures projects remain cloneable while protecting sensitive configuration data and providing clear setup instructions for new developers.