Once set up there’s really only one variable to control, bid. Often these campaigns will perform very poorly at a high bid, so we must continually reduce the bid until we find a bid that performs at a reasonable ACoS.
You will eventually reach a point where the bid is too low to get any clicks so if you’ve lowered the bid to this point and it’s still not profitable, then the only action is to shut the campaign off.
It’s really this simple! Maybe in the future Amazon will beef up their retargeting ads, but for now, it’s super simple and either works or it doesn’t!