Infrastructure as Code (IaC) eliminates the manual, error-prone process of clicking through cloud consoles. Terraform lets you describe your entire infrastructure in declarative HCL files that can be version-controlled, reviewed, and tested.
Organise your Terraform code into reusable modules. A module for a PostgreSQL RDS instance, for example, should expose only the variables that differ between environments (size, storage, name) and hide sensible defaults inside.
Always use a remote backend — S3 with DynamoDB locking on AWS, or Terraform Cloud — so state is never stored locally. Losing your state file is catastrophic; locking prevents concurrent applies from corrupting it.
Use Terraform workspaces or separate state files per environment (dev/staging/prod). Never apply to production without first running terraform plan and reviewing the diff in a pull request. Add a CI step that comments the plan output directly onto the MR.
Protect long-lived resources with lifecycle { prevent_destroy = true } and use targeted applies (terraform apply -target) sparingly and only in emergencies.