So we have been to a LOT of weddings =) I also keep up with the trends by reading magazines, watching event specials and attending social events that are thrown for party planners.
Centerpieces seem to be one of those things that gets overlooked in the wedding planning process. It tends to be one of the last things that gets crammed into the already full heads of a wedding couple. It is fine that these pieces aren't thought of until the end of the planning schedule, but make sure that you do put some thought into it.
For example...if you're going to mix candles and flowers, don't put the candles UNDER the flowers. As you can imagine, you'll either wilt the flowers or set them on fire. And you don't want either of those things happening.
If you have a reception hall where the ceilings are high, this is the perfect opportunity to go grand with your centerpieces. Even if they are simple, having vertical pieces will fill the room better and help balance the look of the hall.
Having a very tall structure to place a large floral arrangement on, having the arrangement made of branches and other tall pieces, or even hanging arrangements from the ceiling to hover over the tables are ways to fill in the space.
On the other hand, if you have low ceilings, you will want to keep your centerpieces low to the table so you don't draw the eye up...you want to keep the focus on the details you have designed.
Creative centerpieces don't even have to include flowers or candles. They can be a pie for the table to share, a glass bowl full of sand and sea shells, a tree with crystals hanging from the branches, or an object that you and your fiance share an interest in collecting. A couple of framed pictures of the two of you throughout your relationship or of family members makes a very personal touch that gets the conversation going. Even an arrangement of the guests' favors for taking home later that night.
The biggest thing to remember about centerpieces is that if you want your guests to enjoy each other's conversation, don't place a centerpiece in the middle of the table that they will have to talk around. There is nothing more annoying than to be bending your head this way and that trying to make eye contact with the person across the table.
So either go for a high or low centerpiece and make sure people can see each other. Make sure that the centerpiece is proportionate to the table so there is room for the dinnerware and condiments and remember that simple is usually the best way to go!