Grouping by tags
Campaigns should be tagged by their Topic and Medium, so that you can group related campaigns together for reports. A campaign can have more than 2 tags, if the Topic falls into a logical category of Topics, or the Medium falls into a logical category of mediums. For example, if you are creating a Campaign for a white-paper that talks about Safety, and will post it on Facebook, you should add tags for:
The Medium: Facebook
The group for this Medium: Social Media
The Topic: Safety
The Group for this Topic: White Papers
For blog posts and webpages:
The Medium: Blog or Pages
The group for this Medium: Website
The Topic: Safety
The Group for this Topic: White Papers
For paid ads:
The Medium: Google ads
The group for this Medium: Paid search
The Topic: Safety
The Group for this Topic: White Papers
This best practice fits most business models, but feel free to add additional tags to group campaigns together logically.