Most engineers want to keep their Google Kubernetes Engine (GKE) clusters highly available, secure, and cost-efficient. To achieve this, they can use 13 optimization tactics divided into three core areas: resource management tips, choosing the right topology for their cluster, and bin packing nodes for maximum utilization. Resource management tips include using autoscaling capabilities such as Horizontal Pod Autoscaler (HPA), Vertical Pod Autoscaler (VPA), and Cluster Autoscaler to control costs and ensure workloads perform well during peak load. Choosing the right topology for the GKE cluster involves selecting between regional and zonal topologies, with regional clusters offering higher availability for the cluster's control plane API. Bin packing nodes for maximum utilization is a smart approach to GKE cost optimization that involves adding pods to nodes in a compacted way to reduce costs without impacting performance. Additionally, implementing cost monitoring, using spot VMs, boosting control plane security, protecting node metadata, and upgrading GKE regularly are crucial steps to ensure the cluster's security and efficiency.