I used to do a lot of weddings when I had the flower shop.
One very simple, but elegant table decoration is a brandy snifter with a single flower floating in water. I like using a large mum or a gardenia, but any flower, fresh or silk, will work. Set the container on a piece of leather leaf fern or other attractive leaf which has been sprayed with leaf gloss. If the guests are sitting at long tables, set several snifters down the length of the table. You can purchase the leaf gloss from your florist.
Candles are always a nice addition, but I'd advise buying dripless candles from your florist. I've had bad experiences with the cheaper ones.
Buy some oasis from him as well, and cut to fit a saucer or other low container and place three candles in it, then fill in with evergreen trimmed from someone's bushes. Spray the evergreen with leaf gloss once the arrangement is done and dust with a little silver glitter.
The items I mentioned buying from your florist may also be available at your craft store.