How do you make a horse stand still when they have a cart or cutter attached to them?

The reason why it is not standing still is because it is scared of it. You have to work with the horse. But first, you have to ask yourself if the horse trusts you. If you don't have the horses trust anything you do with it that might seem scary he will not cooperate. Try getting a horse book at Borders or a big book store on how to work with them to sooth them.