The best practices for auditing digital marketing efforts vary based on channel mix. As the article rightly suggests, there are several different metrics and means of running an audit depending on where each channel fits in as part of your marketer's toolkit.

It's difficult to provide additional insight in this case without knowing more about your product, industry, niche, goals, and channel mix.

I invite you to contact me and let me know a bit more about the elements I stated above and I'd be happy to provide more guidance on the matter.