How to define an audience

Audiences are a powerful feature for any sales campaign, but too many advertisers don’t set them up, or set them up incorrectly.
Here’s what you need to do…
Define your audience
Go to your ad settings and click Audiences.
There, you’ll see sections for your engaged audience and existing customers.
First, define your engagement audience.
This should be the broadest network of people you’ve ever come into contact with before. Start with a Site Custom Audience of all site visitors in the past 180 days. You can also use custom audiences with lead forms, customer lists, apps, and more.
Then define your existing customers, who are people who have purchased from you before.
Use each custom audience that represents your paying customers. Start with a website custom audience of all purchases in the past 180 days. If you can segment your email list to isolate paying customers, use that too.
In both cases, there is no reason to restrict the definition any more than is necessary. Include your entire email list in your engaged audience, not just certain segments. Include all purchases, not just the most recent ones.
Things to note
A few points to remember:
1. If someone is included in both the engaged audience and an existing customer, they only count as an existing customer. There is no need to exclude people.
2. Certain custom audiences (such as Facebook pages, Instagram accounts, and video engagement) are not available for audience segmentation.
Report
Once set up, you can break down the results of all your sales activities by audience segments. This allows you to view performance and budget allocations between engaged audiences, existing customers, and new audiences.
This was extremely valuable insight and its information helped me change my targeting approach.
Learn more about audiences here.