Registry question: How do I make sure people use my registry? I don't want to end up with multiples…

Registry question: How do I make sure people use my registry? I don't want to end up with multiples of the same thing... Also I'm worried no one will get the big baby items we need :/ I guess I'm starting to stress out since the holidays are coming and no one seems to have any interest in getting our baby items (which is all we asked for Christmas) and then our baby shower is Jan. 10 exactly one month before our due date and I don't think we will have time to buy what we don't get...