Your wedding day will seem to rush by in a blur. After months or even years of planning, it's all over way too quickly. After the taste of the food fades, the hangovers are cured and the Thank-You cards are ready to send, what will you have left to remember your day?
The photographs. They remind you of feelings and emotions that overwhelmed you and your spouse. They remind you of your cousin making a fool of himself on the dance floor, your little sister crying during her speech and the father of the bride beaming like the sun while he danced with his beautiful little girl.
That's why it's so important to choose a professional photographer to document your day. There are no second chances. I've published a post on how to Communicate with your Wedding Photographer, so this post will deal more with the actual logistics.
Make sure that you provide your wedding photographer with a schedule. This ensures that s/he will be in the right place at the right time to capture moments that you have planned (cake-cutting, surprise announcements, funny skits, etc).
Also, discuss the locations of the photos. Sometimes it is better to have the formal family portraits done right inside the church. If you get the large group photos done immediately, then release people as you go along until you're down to the parents, maid-of-honour and best-man, it is a lot easier than trying to keep family members waiting patiently in their seats when they really just want to get started with the festivities.
Off-site photos should be planned with the fewest number of family members as possible. This reduces the stress of not having one or two members get lost on the way, stuck in traffic, or losing track of time at the bar. If you insist on having your entire wedding party included in off-site photos, try to arrange transport using as few vehicles as possible, for the same reasons mentioned above.
An aside not specifically about photography but addressing efficiency; consider having speeches during dinner. Not while plates are banging during the initial service of each course, but when everyone is quietly chatting and chewing. This negates the hour-long banter of inside-jokes that guests have to endure after their bellies are full of food and good wine. When the dinner is over, so are the speeches. Maybe even consider the "first-dances" before dessert is served. When the plates are cleared, get that dance floor polished and enjoy!