Step 1: Prewriting
Step 2: The Thesis Statement & Set Up
A good example of a thesis statement is: Twain uses the growth and development of Huck Finn to show readers what is morally right.
The thing that is most important about a thesis statement is that it needs to be about what you're going to write about. If your thesis statement is about the relationship between Shakespeare and Scooby Doo, then you better stick to it. You can't throw in a paragraph about how Velma relates to Charles Dickens, because it does not fit with your thesis. Everything in your essay should work towards proving your thesis.
Note: If writing about a book you might want to include the title and author in your them statement. Otherwise you can include that info in another sentence before it.
Also multiple sentence theme statements are possible, but can mucky up the point.
Before I write my Essay I use the following set up.
1. Attention Getter
2. Evidence for body paragraphs
5. Tie in to attention getter.
I find it helps when writing to have these before i get too far into it. However, it is completely up to you.