UTM coding can very quickly go awry if you don’t follow best practices. Consistency and attention to detail can be the difference between an easily analyzed set of data and one that provides no insight at all. If you’ve already read my post about UTM coding 101, read below to learn about the different rules to make sure your extra work results in better data.
Keep UTM Coding Consistent
Consistency is something that can be easily missed when you’re sharing your UTM coding duties with others. When choosing your source, medium, campaign, and ad content, make sure you use the same pattern and nomenclature. For example, you’ll need to decide whether you name your source facebook or fb and stick with it. You may find it helpful to keep a Google Doc that you share with your coworkers to remind all of you the naming conventions you decided on.
Plan for growth with your UTM Codes
When naming your campaigns, think about possible future campaigns and how to categorize them. For example, your campaign name shouldn’t be fall-sweaters if you plan on selling lawn mowers in the future. A more applicable campaign name might fall-clothing or just fall-promotions.
Don’t use profanity in Your UTM Codes
Although this may seem like an obvious recommendation, remember – users can see your UTM coding when they look at the address bar in their browser. Don’t use profanity or other inappropriate wording unless you have a strong desire to be called in by your human resources department.
Only Use Lowercase in Your UTM Codes
The suggestion to only use lowercase in your UTM codes comes from a “better safe than sorry” place. Having both uppercase and lowercase ad content increases your chances of inconsistency. This inconsistentcy can split up your data and can cause you miss larger patterns in your data.
Even more important though, using uppercase can throw off the source and medium for Google and make it unable to be categorized into a specific channel (for more on sources and mediums, see my blog article here).
Don’t Use Special Characters in Your UTM Codes
This is another “better safe than sorry” recommendation. Spaces and special characters in your UTM code increase your chance of breaking the URL. This is a factor that can vary based on browser and the server configuration you currently have on your website. If you’re still insistent that your words be broken up somehow, I would recommend using dashes instead of spaces to separate out words.
Always Use Source and Medium in Your UTM Code
Your UTM code won’t work without a source and medium. While you may think you’re saving time by not including this information in your UTM code, at the end of the day the joke’s on you – none of the information you typed into that UTM code will make it to Google Analytics. 
Summary
In the words of Monica from Friends “Rules are good! Rules help control the fun!” The same can be said for UTM coding. By following the rules above, such as always using lowercase and never using profanity, you can be sure that your dive into data is a party for more ROI, not a funeral for your analytics. Be sure to check out Best Practices for UTM Coding Part 2 and where you can use UTM coding.