1. Communicate the must have shots to your photographer. If you've hired a professional, there shouldn't be any need to tell him about the standard set of must-have's, but rather if you see something on the web or in a magazine that totally grabs your heart, be sure to forward that link or article in advance (it might be difficult to verbally describe on the wedding day).
2. Delegate. Choose a friend or relative that knows a good number of folks who will join the formal pictures. Get this person a shot list and have them help corral everyone for each picture. This speeds up picture taking and allows your photographer to focus on composing and taking great portraits. Also consider not to getting carried away with your shotlist. Assuming your photographer is slanted toward a journalistic approach, he/she will likely can get far more interesting candids of all the bubbly happiness following the ceremony.
3. Plan carefully about how much time you allot to taking pictures. Even the best photographer needs at least 10 minutes to do a good set of portraits. Consider doing bride/ bridesmaid, groom/ groomsman photos before the ceremony, which will reduce time needed for post-ceremony photos. Even better is to do all the portraits ahead of the ceremony. This option really has tremendous upside (if one can set aside the superstitions) 1) you get to have a private moment before all the non-stop craziness starts, which should help alleviate some anxiety and stress you might be feeling. 2) Your photographer can capture that amazing moment when you first see each other– these shots are FULL of wonderful emotion and make GREAT photos. 3) Getting these out of the way ahead of time allows you to enjoy more of the reception.