When containerizing a Python application with Docker, it's essential to follow best practices to ensure security, efficiency, and reliability. This includes using explicit and deterministic Docker base image tags, separating dependencies from source code, and running containers with least possible privilege. Additionally, Python applications built for production should use WSGI servers like Gunicorn, handle unhealthy states through health checks, and find and fix security vulnerabilities in their container images using tools like Snyk Advisor. By following these best practices, developers can create secure, efficient, and reliable containerized Python applications that meet the demands of modern software development.