Curiosity usually grows when people see something that promises helpful information without giving everything away too early. A simple way to do this is to start your ad with a question or short statement that points to a common problem. Then you mention a solution but keep a small part unseen so they want to click to learn more. Sharing a short result or a brief story also pulls people in because they want to know what happened next. I feel curiosity works best when the message is clear and not confusing. Too much mystery can push people away, but a little spark encourages action. What do you think?