You don't have to be a good writer to write well. Writing is a process. By learning to treat writing as a series of small steps instead of a big all-at-once magic trick you have to pull off will make writing a composition much easier and much more fun. You can learn to brainstorm main ideas before you start writing, organize a draft of those main ideas, and revise your composition into a polished essay. See Step 1 for more information.
A number of famous actors have played the role of Mercutio. A small sampling follows.