When I've been building followers manually I've found it a lot more effective to follow people who have just liked a post by a relevant account, rather than that accounts followers.
What would be great is to find posts by a target account within a specified time, ie. last 30 minutes, or ideally even less, and follow the users who have liked it most recently. That way you're much more likely to follow a user who is still actively browsing instagram, and thus more likely to follow back.
When I've been building followers manually I've found it a lot more effective to follow people who have just liked a post by a relevant account, rather than that accounts followers.
What would be great is to find posts by a target account within a specified time, ie. last 30 minutes, or ideally even less, and follow the users who have liked it most recently. That way you're much more likely to follow a user who is still actively browsing instagram, and thus more likely to follow back.