Managing access to AWS resources through IAM is crucial for maintaining security and proper management. Best practices include avoiding root user credentials, attaching permissions to groups instead of individual users, aiming for least privilege permissions, focusing on separation of duties, enforcing multi-factor authentication, leveraging the natural security boundaries of AWS accounts via a multi-account environment and AWS Organizations, making use of AWS Identity Center and Federation, utilizing roles as much as possible, avoiding inline policies, regularly reviewing permissions, and extending your AWS fundamentals beyond IAM. By following these practices, you can help ensure that your AWS environment is well-managed and secure.