Go Tropical

Do you like the idea of getting married at the beach, but not the idea of a plain and simple wedding? Sure, the very concept of the beach is minimalistic: minimal clothing, accessories, makeup and, well, you know, minimal clothing. But you can still have a luxurious wedding at any beach by embracing a tropical theme. You don’t even have to go to Maui. If you plan to get married on a beach, take advantage of the sultry ambiance and add as much color as you can. Chair sashes in rich tropical colors like salmon, royal blue, magenta, lime green, sunny yellow, bright orange, embellished with orchids, roses and hibiscus add some lavishness to the ceremony. Add some extra flavor by using tropical fruit as decoration, such as mangoes, pineapples, watermelon, and bananas. And don’t forget to make the most of the natural beauty you can find only at the beach: seashells. Pink conch shells look nice placed at the end of each row of chairs. Glittering the sand with smaller shells is also nice. Just make sure the guests are wearing shoes.
(Visit http://www.weddingthemes.net/wedding_themes_island_style.htm for images)

Add a twist to tradition:

Rather than candle unity, incorporate sand unity into your ceremony. The bride and groom each hold a vial and fill it with sand from the beach. Then, simultaneously, they pour their sand into a larger vial or bottle, symbolizing their lives merged and unified. You can find an ornamental bottle, or decorate one yourself. Keep the bottle of sand as a keepsake and constant reminder of your vows.
(This idea from http://www.alohafriendsluau.com/Hawaii_wedding.html )

If you can't make it to a beach,utilizing a tropical decorative theme can make a backyard or outdoor wedding appear and feel exotic.