Some of the essential preparations when communicating to inform, persuade, and argue includes;
Determine what you know about the subject.
Be mindful of what your audience already know about the subject and avoiding stating mainly what they know already; so they will be more interested in what you have to say.
Use appropriate language and terms that your audience can easily understand.
Make references to respectable outside sources that back your claim.
Respectfully present your speech to your audience, and avoid been judgmental because of their differing views.