Choose a post that gives people something to answer
Comments read as conversation, so the post has to contain a prompt someone could plausibly respond to: a choice between two options, a question about a tutorial step, a request for recommendations or a debate the caption sets up. A scenic photo with a one-word caption gives commenters nothing specific to say. If the prompt is vague, rewrite the caption before ordering so it ends with one clear question people can answer in a few words.
Carousels and Reels both work, but the comments should suit the format. A carousel comparing products invites people to name a favorite, while a Reel showing a process invites questions about a step. Write three or four example replies a genuine follower might leave. If you struggle to imagine them, the post is probably not built for discussion, and visible approval or a different post may suit the budget better than a comment thread.
