When you're shooting your formal shots, the height that you position the camera is actually very important, because if it's not positioned correctly, your subject's body can look distorted or some parts can look larger than normal (in general, this is just not good stuff). So, finding the right height for professional portraits is critical. Here are a few guidelines to help you get the pro look:
Standing, Full-Length Portrait: Position your camera (on your tripod) at the bride's waist height (yes, you'll have to squat down/bend over, etc., but the final result will be worth it). Keep your lens straight (don't aim up towards the bride's face).
7/8 Shots (from the Calf Up): Position your camera (on your tripod) at the bride's chest level and shoot with your lens straight from there.
Head and Shoulders Shots: Position your camera (on your tripod) either at the bride's eye level or slightly above