Before Beethoven was able to create his 5th symphony, he learned the song "Twinkle Twinkle Little Star". Before any of you poured over your text book for that last class you were cramming for, you were reading "See Spot Run". My point is that we all start somewhere.
Now that you have learned how important a growth mindset is for your development I am going to teach you a little about structure. Now it is true that the President of the United States for example doesn't always speak in a structure... but if you pay attention close enough you will discover that often times, they do! Structure is a superb tool for the novice speaker because it gives you parameters to work off of AND good structure always leaves a good impression of competence.
Teaser - An attention getting device devised to bring your audience into your speech. This can be a story, shocking statistic, etc... but it MUST grab the attention of your audience.
Thesis - One distinct sentence that tells your audience what your speech is about.
Preview - This area of the speech highlights the major points you are going to cover in your speech. In most good speeches you say what you're going to say (Preview), say it (main points), and then say what you said (review).
When considering structure I recommend the two approaches described in the following videos.