Here are the three things a good officiant should do:
1. Keep the ceremony special. Your wedding is a big deal; aside from all the planning and reception details and guest lists and issues, it is a major step and enormous, holy commitment. I plan the ceremony with the couple--presenting options, asking questions, going over details--to make sure it is what the couple wants, needs and desires.
2. Run the rehearsal and reassure the couple. This seems like an odd one, BUT, the day before your wedding, you are going to be so far past wanting to deal with last minute hiccups and surprises, and inevitably, someone missing a cue (or missing the rehearsal) can seem like the end of the world. I have experience in stage management in addition to being a liturgical church nerd and prolific wedding officiant--I promise the couple that everything will line up as it should as we rehearse and prepare; it takes the burden of worrying about the ceremony away from the couple.
3. Get to know the couple. I hate generic weddings. In three sessions in person or via Skype, I get to know you both--how you met, why you're the one for the other, and what you're hopeful about and worried about. If you desire traditional pre-marital counseling, that, too, can be arranged. Knowing y'all, and asking questions, and hearing stories, helps me present you two as actual people getting married, rather than strangers who hired me off the internet.
Hit me with any questions you've got.