Make sure to tag every instance/resource/disk in AWS, with their purpose, team, etc... Then you can go into the AWS costs explorer and see the costs breakdown

Make sure to tag every instance/resource/disk in AWS, with their purpose, team, etc... Then you can go into the AWS costs explorer and see the costs breakdown per tag. Usually there will be a few resources standing out. 80% of the costs is 20% of resources. Find out what they are and cut.