Originally published in 2012, we have updated this post to keep our audience in the know about the ubiquitous and best (in our opinion) tag manager system available, Google Tag Manager. Last updated September 16, 2015

Is your website tracking team struggling to keep up with the variety of tags and tracking codes needed to compete online in your industry? It takes a great deal of time and patience to learn the particulars of manually installing tags in the code of your website. Successfully managing tags can take the expertise of a web developer to do it correctly when working with a large or unique site. For the past few years though, Google Tag Manager, GTM for short, has been a force of nature for marketers wanting to take control of their tracking initiatives.

To learn how it works, beginners may want to take the Google Tag Manager Fundamentals course, which is free to take, while advanced users may want some more instruction beyond that introductory level.

Three Deep has been a holder of a partner certification with Google Tag Manager since it was introduced, and have been managing GTM containers for enterprise clients of all types and sizes, so we have created a summary of the helpful tool for you here.

What is GTM?

Google Tag Manager is a tool from Google that is free of charge and consolidates most of your website tags with a single snippet of code. With a variety of tags, rules, and macros, marketers now have a wide spectrum of tag options for all of their campaigns, including AdWords, Doubleclick, and many more.


 GTM tag menu

An example of common tags are those from Google itself. Google Analytics (GA) event tracking and Google AdWords remarketing tags are powerful tools that give advanced insights into your website visitors’ behavior and how you can ultimately convert them into customers. With GTM, the biggest advantage is that you are able to manage these tags and more from a web interface, so you can add and update your own tags, goals, and tracking priorities with just a few clicks, whenever you want. With that flexibility you can let your webmasters focus on other important tasks and you don’t have to be responsible for editing (or goofing up) the code in your website.


 GTM built-in variable checklist

GTM makes it easy to be sure your tags are firing correctly with an automatic “Preview Mode” that is available when you make changes to tags. This allows you to visit your website and check that the tags are firing properly and the correct data is being collected before clicking publish to make the changes public.

When you visit your site in preview mode, the bottom part of your browser displays an interactive menu with information about how the existing tags are firing as you click through the site.


GTM preview mode

The preview mode doesn’t just show your tag labels, but also shows the triggers and variables that have fired on the page in the form of JavaScript code. Because JavaScript (JS) is the basic language of GTM, creating custom dimensions, metrics, and variables takes some advanced knowledge of JS code and regular expressions (RegEx), so managing GTM isn’t exactly for the digital marketing layman or generalist. Setting up a GA code is simple, and there are helpful guides available, but advanced remarketing and other website tags will likely take some time to master.

Learning how to use GTM at an expert level takes time and experience, as well as knowledge about tags, conversion tracking, and some understanding of JavaScript and RegEx, but getting started with the free fundamentals course is a good place to start.

What Does the GTM Fundamentals Course Cover?

Recently several of our team members passed the GTM Fundamentals Course from the Google Analytics Academy. This course offers individuals videos and transcripts to help you understand:

  • How to create a measurement plan and tag implementation strategy
  • How to correctly implement the tracking code
  • How data is processed using the tool
  • How to create, validate, and manage tags properly
  • How to create custom dimensions and metrics
  • How to setup tracking of conversions, goals, and events using variables and triggers
  • How to set up AdWords conversion tracking and Dynamic Remarketing

The course is free and there are sometimes certificates of completion available, but it’s simple enough to pass when you take the time to follow the stellar study guides. A highlight of GTM fundamentals is that it walks you through the process of setting up commonly used tags in the context of an online business, so you can glean situational and strategic insights from the videos, not just how to use the tool general.

When studying for the course, you may like to refer to these transcript guides:

Unit 1

Unit 2

Unit 3

Unit 4

How Can You Maximize GTM?

Making this tool work for your company is a simple matter of having a solid measurement model for your online marketing and properly using the tool. Since we are a Google Analytics Certified Partner, Three Deep was among some of the first to try out this product in Beta. Since then we’ve managed implementation, migration, and housekeeping of Google Tag Manager for many of our Web Analytics clients. Here are some areas of focus that help us maximize GTM for our clients.

User Defined Variables

One of the powerful features of GTM is the ability to create user defined variables. This is a way to make variables that can be used in many places, such as a GA account variable, and can be modified in one place, the custom variable menu.


If you need to set up event tracking and the markup does not have element ID's you can use the DOM Element variable to create a custom CSS Selector. If you need to expand your knowledge of CSS this is a fun game that teaches you how to navigate the DOM elements using CSS selectors.

Be Mindful of Tool Updates

Since this tool is used by so many individuals and businesses, Google is often publishing updates. It’s smart to keep an eye on this Release Notes page, and even set up a change detection alert to make sure you don’t miss any new features or changes that occur.

Some recent updates to GTM include:

  • Real time data validation using the Tag Assistant "Record" function
  • Custom HTML fields now have syntax highlighting and coloring in the editor
  • Folders are now available to organize your tags, triggers, and variables

Keep an Eye Out for New Third-Party Tags

To simplify setting up third-party tags, Google has created an open format template program for tag vendors to help marketers implement their tags. When a template is approved, it is added to GTM for users to implement and makes the integration process much more user-friendly.

Install Tag Assistant

Google Chrome’s Tag Assistant plugin is a valuable tool to check the tags that are firing on a given web page. It gives a list of tags on the page as well as insight on the status of the tags which are color coded. Google’s descriptions of the codes are as follows:

  • A grey icon with an 'x' indicates that no code was found on the page
  • A green indicator will show if a valid tag was found. The number in the icon indicates the number of tags that were found
  • A blue indicator will show there are suggestions on improving overall tagging health
  • A yellow indicator will show that a tag was found with minor implementation issues
  • A red indicator will show that a tag was found with critical implementation issues tag-assist

 Valid tags firing on Three Deep's blog

Common Issues

When coordinating a GTM container for your web properties, there are often roadblocks that can get in your way. Here are a couple tips for staying organized with your tags and keeping your data clean.

Managing Tags

Some large website have issues with managing many tags at once. In this case your team should use naming conventions and the new folders feature to organize tags. The container can be organized like any digital file manager and should be treated as such so you don’t end up with ambiguous and duplicate tags that are hard to identify. Teams in different parts of your company may want to place similar tags on the same page but for different campaigns, products, and other purposes, so sticking to a simple naming scheme is a good idea.

Verify Container Installation

Depending on your website, it can be challenging to be sure your GTM container tag is on all pages of your site. Sometimes content management systems provide “code injection” tools so you can add code through all pages at once, but it’s better to make sure you don’t have any gaps. In addition, GTM must be implemented in the <body> tag of a webpage, unlike the GA tracking code which has always been implemented in the <head> tag. Using a crawl tool like Screaming Frog can help quickly identify the pages with or without the JavaScript tag manager code, giving you a fast answer instead of checking manually.

Redundant or incorrectly applied tags can distort your measurement and result in duplicate costs or missing data. It’s best to only use GTM for tracking tags if you’re going to use the tool, so removing old tags in the code is important before implementation. As mentioned above, keeping a consistent naming convention can help your team from duplicating and muddling tracking efforts within Tag Manager itself.

Excited Yet?

We are very excited for the potential that GTM brings to new clients and current clients alike. Making it easier for marketers to analyze user behavior and improve the success of campaigns is good for all web users. If you’re a current client of Three Deep, we are excited about improving your campaigns with this ever-evolving tool.

Building your technical knowledge of the tool is important, and GTM Fundamentals can help, but there is additional certification available for users who are part of their company’s partner account, which is what Three Deep has achieved. This partner certification is much more detailed and in-depth than the Google Analytics Academy course, so when an organization holds that badge, you know they have deep functional expertise in tag management.

If you’re using GTM already, how is it working for you? Please let us know in the comments.

If you’re interested in learning how Three Deep can help you more effectively use Google Tag Manager please contact us today.