20 guests is a reasonable sized wedding. Start with planning lodging for everyone, then move to how you will feed them. Making small favors will be much more personal then store bought ones. The dress your guests wear will be determined by the time of day the wedding is held. Give everyone plenty of advance notice.
First step is choosing your partner. Do it as early as possible. Then write down the names of the persons who are closer to you. Inform them about your wedding. that's it.
Jamaica has an Internet site for tourism. You can go there and look at their section about weddings. You can also hire an American wedding planner who would do all of the legwork for you.
