Creatures respond to stimuli in different ways. You need to know your audience. Then find the right mix of image, language, tone, and content.

 It's not just what you say, but how you say it.

A great image (whether in an ad or Facebook post) draws attention and gets people to read the headline.

 And if the headline is interesting (MAN BLOWS AWAY DUCKS), they read the first line of copy. And if that's good they keep reading. Or swim in your direction.