It is important that you lead and the other person does not deliberately try to help or to hinder you. This is called contact mind reading as you are touching the other person as you work. This is not as good as non-contact mind reading, but still makes a very impressive demonstration of your abilities. Once you can do it easily by contact mind reading, try and do it without touching the other person. You will find this a great deal harder, but the ultimate results make the effort well worth while.