I am not sure how lucky you are if you sell high value items or services door to door however many people choose it as a profession. Some people sell cleaning products etc that may be of fairly low value and traditional sales methods may work well in these cases.
However if you sell high value goods it is what we call a major sale. The skill set required is very different and there are many reasons why. Research has shown some people have natural skills making major sales and others need to learn those skills. Selling door to door requires great discipline and if your items are expensive it is possible there may be more than one call required to any prospective customer. There are good courses available on making door to door sales out there but you really can’t go past the book “Spin Selling” by Neil Rackham.