Teaser captions are fun to write, but they don't give anyone a reason to stop, comment or come back.
Caption: "big things coming 🚀"
Score: 2/10, "Vague promise, zero substance."
HAITE (dial 7): "It's the caption equivalent of a blank cheque written by someone with no money. 'Big things' tells me nothing, and the rocket emoji is doing all the work a real word should be doing. Say what the thing is, or don't say anything."
People respond to specifics: a date, a price, an opinion, a question they have an answer to. "Big things coming" gives them nothing to respond to, and because anyone could post it, it doesn't tell anyone why to follow you in particular. The emoji sets a mood, but it can't say what you mean.
"Our [product] goes on sale Friday at 6pm. [One plain reason someone would want it]. The first [number] orders get [a real offer]."
"Spent [time] making this. It does one thing: [what it does]. Out [date]."
Paste your work into HAITE and it will tell you what's wrong with it. You set how harsh it is, from 1 to 10. It's free to start.