Having a good setup on Google Analytics is very important, as you will be able to identifiy the results of your marketing activities per campaign, ad, audience, and tactics.
UTM tag example:
The source should be the ad network provider, like facebook or google. You can also use it to identify the dsp, like mediamath or dbm. Example: facebook
The medium should be the marketing channel, like display, social, email, rtb, etc. Example: social
Here is the campaign name. Example: de_ppcland_social_facebook_bestnewslettera001
Typically this field is for the ad content. This will allow you to retrieve statistics according to each ad that you ran. Example: facebook_bestnewslettera001_red_text1
Here we used the audience. In this case, we did not use any audience, so we name it RON. We opt to identify the provider before, as different networks can have different audiences. Example: facebook_ron
One best practice: avoid to use spaces or special characters or you can end up having strange names on your Google Analytics.