Most people are familiar with going into their Channel reports within Analytics to see the breakdown of their traffic by Organic Search, Referral, Direct, Social, etc. In fact, this is probably where most people spend the majority of their time.
But fewer people know that you can customize those channels, and add to them as necessary. One important channel that people should consider adding is Paid Social... as you wouldn't want that inbound traffic to be lumped in with "Paid Search" (since it's not from a search engine) or with "Social" since you want your paid efforts to be separated from your organic results.
One way you can do this is shown in the attached graphic. You can reach there by going to Admin within your Analytics, and then in the 3rd column, clicking Channel Settings and then Channel Grouping. You can then create the new Channel by clicking Define a New Channel and defining it as shown in the graphic, and after you hit Done, be sure to hit Save at the bottom.
Another channel that I've recommended in the past have been for Employee Advocacy, but you might find other uses for this functionality such as print advertisements, partner traffic, affiliate links, etc.