Table Setting
Centerpiece-making is a lot of fun: most often, it involves arranging decorative plants and artifacts in a pleasing way, using lots of creativity. At the same time, it doesn't have to take much effort at all.
The Holiday centerpiece is best made beautiful, but without complex symbolism: this is because, sitting on the dinner table between guests, it will be viewed repeatedly by many eyes. You want those eyes to be aesthetically pleased, but not distracted from good food and celebration.
What counts as complex symbolism? Miniature figures, religious or otherwise. If the thing, like a statuette or sculpture, is an important part of a story, leave it out: put it on your tree, mantelpiece, or some other place for prominent display.
If Santa Claus, Rudolph, the Christian manger scene, the Jewish menorah, Christmas trees, Frosty the Snowman, and other symbols aren't included, what's left in? Texture, light, and color of the familiar, simple, and seasonal variety.
You have many options for coloring: the traditional red and green of the season are often chosen, but can look garish and cartoonish on classily-set tables. It's often better to keep the reds and greens subtle, used as accents for colors more likely to suit your tableware: silver, gold, white, brass, clear glass, and copper.
For lighting, candles are great, as long as they're kept out of reach of children and heavy drinkers, of course. If you don't have a nice overhead light like a chandelier in your dining room, accent the table with candles or faux tea lights, which are battery operated and inexpensive. They're programmed to flicker convincingly.
Some people suggest edible centerpieces, with candy and other treats, but this is arguably not a good idea for the holiday dinner table: it could lead guests to spoil their appetites before the main course. If you still are intent on having a candy, fruit and pastry centerpiece, it's probably a good idea to keep it hidden until dessert, and bring it out to complement cake and pie.
Your potential materials are practically endless, but here are a few ideas: a glass bowl, a wreath, some sprigs of holly or evergreen, pine cones, ribbon, nuts with the shells on (for show, less than eating), and Christmas tree ornaments; specifically, shiny balls of varying sizes and multiple colors. Poinsettia flowers and holly are beautiful but poisonous, especially to pets, so evaluate that risk if you have a dog or cat.
If you have both a glass bowl and a wreath, place the wreath on the table, and the bowl in the center of it. When adding ornament balls to the bowl, point the "tops" (where the hook usually attaches) downward to hide them. Sprinkle the nuts on top, or intersperse pine cones with the balls, and add some green: holly sprigs or poinsettia flowers could be poked between the balls, or use evergreen as a pet-safe option. You could also sprinkle some glitter on top for added shine.
The above is only a single suggestion, however: once you've gathered your materials, it's up to you to make an arrangement that fits the table, setting, guests, and very importantly, pleases the eye. Don't get nervous about it - it's easy, can be done with the decorations you already have, and if you don't like your creation, nothing is ruined or wasted: just rearrange and try again until you like what you see!