Tropical Wedding Ideas

I am planning to have a Tropical themed wedding next spring. The problem is, I live in the middle of Iowa, lol. I am looking for any ideas concerning the theme. I bought large, gorgeous shells for the reception table decorations while I was in the Caribbean. I love bright colors such as tangerine, coral, aqua, etc. Which I think would look great with chocolate brown. I think the wedding will be unique but I do not want it to look cheesy or fakey. I am having all of the music played on the marimba accompanied by piano so the music will lead to a Caribbean feel. Any ideas, please let me know - thank you in advance for your help!!!
Tiffany