After hundreds of successful weddings and some real disasters, I find there are three essential components.
First, treat your officiant and vendors as highly-skilled professionals and not as servants or hired hands. They want to do their best work for you, let them! That means committing to the wedding process, listening to their recommendations, and responding to their requests in a timely manner.
Second, hire an experienced wedding planner. These folks have done hundreds of weddings and intimately understand how to manage the myriad of details to execute a superb wedding.
Third, hire a great wedding DJ / sound technician. Whether indoors or outside, there is nothing more disappointing than for a couple to spend months creating the ceremony of their dreams and only to have it heard by those in the first row.