You have already understood that successful targeting has three components: a well-chosen audience, a well-written ad, and a well-prepared platform. Talk about the audience.
When you work with a targeted advertising strategy, the easiest way to go is from the most interested audiences to the coldest ones. It is in this order that I will tell.
These are the “warmest” audiences - those who have already somehow interacted with you: your clients who have visited your site, subscribed to the newsletter or saved an Instagram post. Usually the most effective is advertising just for an already familiar audience, so it should always be tested first.