It's so much fun to be creative with decorating tabletops. The possibilities are endless, but here are just a few ideas....
Candles - This is something that you can leave simple or dress up. A table scarf will make it more fancy, but 3 simple taper candles (in holders, obviously) can just add a nice little touch.
Flowers - Obviously this is easier in the summertime. If you have a flower garden it's a lot of fun to have fresh flowers for the tabletop (and cheap too). Most people love flowers!
Large, wide vase with white or cream pillar candle (tall) - Around the candle you can place small stones, red berries (pretty around the holidays), sand, or potpourri.
Floating roses in a bowl - This idea can be used as a center piece, but also for place settings. I saw the idea in a book... each place had a small bowl with a single rose top, floating in water. It was so cute!
Map under a clear table cover - Our family used this idea for several months and it was a lot of fun. The kids played geography games during meals sometimes. You can either use a world map or a US map. Educational and entertaining!
Goldfish in a glass bowl - Mother saw this at an event she and Daddy attended one time. The hostess had three, clear, various shaped bowls/vases with water and goldfish. The kids at the event got a real kick out of it!
Use your imagination. I mean, don't do anything too weird but there are a multitude of things you can experiment with! Have fun, girls.