I agree totally with Mark. It is better to have 2 cameras at a wedding shoot as one can capture the main shots while someone else can capture the cutaways and reaction shots as you'll need these at the editing stage to cover over wonky zooming and focusing problems. If you are the main camera person, get yourself up beside the groom on his lefthand side and preferably using a sturdy tripod stay there until the vows are exchanged. You'll get shots of the couple exchanging vows and putting the rings on their fingers plus the inevitable kiss at the end. Either use a tie clip mic on the grooms lapel to record sound or use a directional mic on a mic stand to get good audio. And remember to arrive early and do a recce of the building.