AWS cost optimization requires continuous monitoring and right-sizing. Start with AWS Cost Explorer to identify spending patterns. Use Compute Optimizer for EC2 instance right-sizing recommendations. Implement auto-scaling to match capacity with demand. Use Spot Instances for fault-tolerant, flexible workloads. Purchase Reserved Instances or Savings Plans for predictable workloads. Implement S3 lifecycle policies to move infrequently accessed data to cheaper tiers. Use S3 Intelligent-Tiering for automatic cost optimization. Delete unused EBS volumes and snapshots regularly. Use Elastic Load Balancing to distribute traffic efficiently. Implement to reduce data transfer costs. Use RDS Reserved Instances for database workloads. Monitor data transfer costs between regions and services. Tag resources for cost allocation and tracking. Use AWS Budgets to set spending limits and alerts. Implement automation to stop non-production resources after hours. Consider Graviton instances for better price-performance. Review and remove unused Elastic IPs and load balancers. Regular cost audits prevent bill shocks.