The main difference between a speech and an essay is the delivery, but because the delivery is different you have to make some changes.  You need to use repetition, since your reader cannot re-read.  At the same time, you should use signposts, or transition words, to tell your listeners that you are moving forward.

Giving a speech encompasses the following steps:

I. Choose a topic.  Something you know about or better still something that you want to learn about, i.e., a sport, a person, a hobby, an event.

2. After you choose the topic, research  and look up lots of  information on the internet about it.  Read the information and decide what you want to say about the topic.  Here is an example of a thesis statement that you might use: Pizzas are my favorite food.

3. Now you need to think of two/three reasons why pizzas are good.

        A.They come in many varieties. Explain and give examples.

        B. They have nutrious ingredients. Explain and give examples.

        C. They are a meal all wrapped up in one food. Explain and   give examples.

4. Now, you are ready to introduce your topic.  Find a quotation that agrees with your point of view.  Or you could use a statistic about the popularity of the pizza.  or you could use an antecdote about eating pizzas.  Choose one and then tell what your speech will be about.  Do not say, "In my speech."" just say something like this:

(First your attention getter) Pizzas are the number one food in my house.  All of my family cannot wait until Friday night because that is pizza night.  (Then give your thesis statement.)

5. After the introduction, you have to figure how to finish your speech.  The first part of the conclusion is a brief summary using different words than in the body  your speech.  Then you want to use another story or quotation to leave the audience laughing or wishing you speech was not over.

The basic rule for a speech is this: Tell them (the audience)  what you are going to tell them; then tell them; then tell them what you have told them.  

Introduction

Body

A.

B.

C.

Conclusion

Giving a speech seems hard at first as does anything worth doing.  The key to this or any assignment is a positive attitude.  You will never succeed if you just close your mind. 

Practice is also an important aspect of speech making. Actually giving the speech to your parents or siblings, tape recording it, saying it in the bathtub, whatever....this will make the speech easier to give. 

Do not try to give the speech with the entire speech written down in front of you.  That will make you a reader not a speaker. Use a few note cards to remind you of the order of ideas.

Last, look at the audience.  It is not easy, but necessary. This will assure the audience that you are speaking with confidence even if you stomach is filled with butterflies.  The key is make those butterflies fly in formation.  In order words, through practice you will be in control. 

Take my word for it because I have been teaching speech for over 30 years, public speaking can be fun!

A speech in the sense you are asking about is to give a talk in public about a concept you wish to explain such as what is Tourettes Syndrome, an idea you wish to persuade your audience to accept such as accepting the handicapped, or a speech to show the audience how to do something like build a skateboard.  Other purposes for speeches exist, but these will suffice for this explanation. You need to know how long the speech must be  and whether you must use visual aids.  You then must decide if your speech is to inform, to persuade or to show someone how to do something.  Once you decide, then write a list of what you know about the topic.  For example, if you decide to inform your audience about Tourette's Syndrome, you might list swearing in public, making noises and moving involuntarily.  To that you might research Gilles de la Tourette for whom the syndrome is named, what other conditions might accompany Tourettes, and famous people who were thought to have the condition.  Each of these ideas could become a "paragraph" in your speech in which you talk about one idea at a time.  A brief outline of what you want to say in short phrases to remind you of the next point you wish to make will be helpful. Make sure that your ideas are in order to explain what Tourette Syndrome is because that is the purpose of this informative speech. Be sure to practice your speech in front of a friend to time it, be confident with the material, and to hear your friend's suggestions to improve it.  If you wish to persuade, think about what information you could use about Tourettes to encourage acceptance of people with handicaps.  If your speech is to show someone how to do something, do it yourself while writing down what you do in the order you do it. This list becomes the basis of your speech. A model to show students as you talk would help this kind of speech.  When you do the actual speech, either look just a fraction above the audience or look at various people you know in the audience to make eye contact which helps the audience feel that you are talking to them and not reciting a memorized speech.  I do hope this helps you understand what a speech is and how to do one for class. 

A speech is very much like an essay.  You need an introduction, a main idea to support, sections of the speech to support the main idea, and a wrap up.  Most teachers require that you give a speech with just an outline or notes, enough to help you remember your talking points.  Being able to give a speech is quite important.  You will need this skill in college, quite likely in the workplace, and possibly in your personal life.  This is a great time for you to get started on this skill.