I go to great lengths every year to make the christmas light display go as smoothly as possible. I typically start with a sketch of the house and place the lights where I would like them keeping in mind the elements that I want to use in the show. After that I can tell where I need to put the controllers. Once I have all the controllers placed, I can then make sure that I have the electrical in place.
Here is this year's sketch. This then becomes a photoshopped image.