What are some recommended best practices for building scalable and user-friendly platforms in social media app development?

I’m exploring ideas around developing a social media app and want to make sure it’s scalable and provides a smooth user experience. Specifically, I’m curious about effective approaches for user authentication, real-time updates (like notifications and live feeds), and content moderation. If anyone has insights or resources that can help guide development in these areas, I’d really appreciate your input!