Enable multi-factor authentication (MFA) for all AWS accounts and IAM users.
Control access to AWS resources with IAM policies and use roles with the least privilege.
Encrypt sensitive data in transit and at rest using AWS Key Management Service (KMS) and AWS Certificate Manager (ACM).
Regularly monitor AWS security events and perform security assessments using AWS Security Hub and Amazon Inspector.
Use VPC security groups and network access control lists (ACLs) to control inbound and outbound traffic to your instances.
Implement network segmentation to isolate different parts of your architecture.
Regularly back up critical data and store backups in multiple locations, including off-site.
Use Amazon CloudTrail to track changes to your AWS resources and auditing purposes.
Use Amazon GuardDuty to detect and respond to security threats.
Automate security-related tasks using AWS CloudFormation and AWS Config.
It's important to remember that security is an ongoing process and that these best practices should be reviewed and updated regularly.