Choose a compelling topic, although in some cases a topic may be mandated by the teacher. Focus on topics that interest and excite you, as this energy and enthusiasm will make your speech more compelling. Select a cause you are passionate about, a subject that interests you, or a hobby you enjoy. Avoid settling for a topic you don't care about, which will almost inevitably lead to a lackluster speech.
Create an outline will allow you to most effectively track your arguments and make sure that your material is arranged in a way that makes sense. Listeners should be able to easily understand your trajectory as your move from sentence to sentence, point to point. Understanding the path you want your speech to take will help you write more quickly--and be able to focus on making your speech interesting and eloquent.
Write the speech. While this may be the most difficult part, the preparations you have already made will simplify the process. Focus on using descriptive phrases, anecdotes and powerful arguments that will engage your audience and keep them interested.
Rehearse your speech. Make changes as you hear awkward phrases, unclear points or a point that doesn't seem to flow intuitively from the statement before it. As you read aloud, you will really begin to hear how your speech will sound to others. Once you have fully revised your speech, keep practicing, this time focusing on presentation. Indicate where to place dramatic pauses, interject humor or grow aggressively questioning. Ask a parent or friend to listen to your speech and give feedback on your content and delivery. Don't be concerned if you end up making significant changes to your speech, as you are just making it more effective.