The most effective strategies for balancing cost and performance for a globally deployed application on Azure include utilizing Azure Auto-scaling to adjust resources based on demand, ensuring cost efficiency, and implementing Azure CDN to cache content closer to users, reducing latency and bandwidth costs. Selecting higher-tier services indiscriminately can lead to unnecessary costs, and deploying in a single region ignores the performance needs of global users. The right choice of services and configurations based on actual needs is key to optimizing both cost and performance.