Study Haiti in-depth. In the writing world, writers are often advised to "write what you know." If you don't know it, learn it. To write a screenplay about Haiti, you should understand the nation's history, culture and politics well enough to write clearly about it. Any topic based on real events, people and history requires accuracy. Even if you are writing about a single event, such as a natural or man-made disaster, international politics and the people of Haiti influence these types of events and the response to them. Critics, movie studios and directors will expect the screenwriter to fully understand what he is writing about. Any inaccuracies could mean that your film will never be made, or will lead to poor reviews and money lost.
Take a screenwriting class. Movie scripts have a certain format that must be followed. Understanding how the content should be formatted on the page and how long the script can be is essential knowledge to writing a great script, and classes can teach you what you must know. Some community colleges and most film schools offer screenwriting classes. The University of California Los Angeles (UCLA) offers extension classes on screenwriting that can be useful for learning how to write scripts and for making connections in the industry. You do not have to be a full-time student to take extension courses.
Read screenwriting books. There are many books that are extremely helpful for screenwriters. Look for books that are updated every few years to keep up with industry screenwriting standards. Because standards change, it is important to have a book that is regularly updated to reflect these changes. Books that include information such as formatting, character creating, and scene building will help you write a great screenplay about Haiti.
Purchase a screenwriting program. Most screenwriters use Final Draft because it is considered the industry standard. Most studios, producers, directors and actors can usually tell when a script is not written in Final Draft, and may not consider the screenplay professionally written merely by looking at the pages. Final Draft also makes writing in proper screenwriting format much easier and has additional tools such as scene-organization templates.