Tag implementation validation can be approached in many ways -- there are some great vendors/services out there at a range of pricing, starting with free!
We recommend validating in any way possible soon after applying tags. You can start by validating data in BlueConic against data from your analytics platform. If you filter an analytics report to show the number of unique visitors in the last 24 hours, this should maintain a close distance (but will not exactly match) from a report you can pull in BlueConic.
To check in BlueConic, head to the Insights area under 'More':
Once you are there, click "Add Dashboard" in the top right:
and then "Add Insight":
Select the "Segment discovery" chart (check 'Show all' if it is not listed):
To show the number of profiles visiting in the last 24 hours, find the "last visited date" profile property below the segment discovery wheel (hint: type "last"):
Begin building a segment of users visiting in the last day:
The number of profiles visiting in the last 24 hours will be displayed: