What makes me different? The details
I attend local rehearsals. This is the perfect way to iron out the final details. I bring the equipment out and I take this opportunity to get music and voice levels correct. I make sure that the processional order is correct. If names are difficult to pronounce, I have each name written phonetically and I double check to see that I am using the proper emphasis. (My last name is Thoma (Toe-mah), so I understand how important it is that names are pronounced correctly.)
I have also found that most people are more nervous during the rehearsal than the actual wedding day. Crazy, right? Having the rehearsal music playing gives them a sense of calm. Psychologically speaking, going through a full-fledged rehearsal complete with music will help the next day, You get to make mistakes, joke, laugh and generally have fun. I also rehearse the Grand Entrance, complete with all of the cheering and hype associated with it. I want them to own the moment and enjoy it. The next day, the entire wedding party feels that they have done it already and it feels comfortable to them. Everyone is relaxed and you have an awesome time.