The guidelines for shooting tables full of guests are fairly straightforward. You’re going to politely ask half the table to rise and stand behind the luckier half that gets to remain seated. Then you’ll line everyone up evenly, being careful not to lose anyone behind a plant, bottle or tall guest. If a large floral centerpiece is sitting in the middle of the table, you’ll move it out of the live picture area.
Make sure that everyone looks neat, that no one is sticking a spoon of food into their mouth, and that the table itself is neat—straighten up or move away (you can ask the guests for help with this) any messy dishes or rumpled napkins. Keep a checklist of the table groups you’ve photographed. If you see an empty setting, ask who is missing. If you can’t locate them, make a note to come back after you’ve covered the other tables.
The lens you use will undoubtedly be one of the wider ones in your bag, and the flash you use should cover the lens’s field of view. An assistant holding a boom-mounted fill flash could round out the lighting and fill harsh shadows. To avoid "frozen-smile syndrome," ask everyone to look away or close their eyes, relax, and then on the count of three, look at the camera and smile. Take an exposure and repeat the process at least one additional time, in case someone blinked. (Trust me... it works!) Assuming your flash can recycle as quickly as your camera’s top-end burst rate, a quick burst of five or six frames will invariably yield one or two blink-free keepers.