Feeds show only the start of a post before “more”: about 125 characters on Instagram, three lines on LinkedIn, a second or two of a video. The hook has to work in that space alone.
Hooks that work are specific: a number, a surprise, a question the reader has asked themselves. A hook that promises what the post doesn't deliver costs trust.
Example
Instead of “New on our menu!”: “We tried 14 versions of this sauce. Number 15 is on the menu from Friday.”