The best centerpiece lets guests see each other. Keep anything in the middle of the table below about 12 inches high, or use tall, slim candle holders that people can see past. Leave room for serving dishes if you serve family-style.
A simple formula works on most tables: a table runner, greenery or a garland down the center, candles, and a few accents such as pine cones, ornaments or berries. Flameless LED candles are safer near greenery and around children, and many have timers.
Measure your table for the runner. It should leave 6 to 12 inches hanging over each end, or sit just inside the edges for a modern look. Napkin rings, chargers and place cards finish the setting for a special dinner. Do a test setup a day early so you can adjust spacing.
Coordinate the table with your Christmas dinnerware, and add sparkle with battery fairy lights woven through the greenery.