Management page of Redshift in AWS Console does not currently allow you to add or modify tags on your clusters. That doesn’t mean that Redshift resources cannot be tagged – almost everything from clusters to parameters groups can be tagged through the Tag Editor.
Once those resources are tagged, Redshift console will show the tags associated with them. Go get to the Tag Editor, choose Resource groups in the top menu in AWS Console. From the drop-down, choose Tag Editor. Or simply go to https://resources.console.aws.amazon.com/r/tags.
Tag Editor allows you to find and modify tags on almost all AWS resources per region. Simply select appropriate Redshift resource (or all!) under Resource types.
If you want, you can select All resource types to see all tagable items in the region.
After you tag all interesting bits, you can group them into a Resource Group. To do that click Create a Resource Group under the Resource groups menu or go to https://resources.console.aws.amazon.com/r/group. After you create the group, it will be available under the top menu, so you can easy get back to it and see everything inside it, even across all regions. It’s an easy way to keep an eye on similar items, check their status, metrics and configuration.