Shmoop's Guide to Writing the Perfect Essay
Here is what the entire essay hinges on. The thesis statement is a sentence or two that comes at the end of your introductory paragraph and does two main things: it states your main point and previews your evidence in support of that point. Be assertive. Be specific. Be arguable—that is, make a point that's interesting enough that you could have a debate about it. The thesis “Hitler was a bad, bad man” is going to be heavy on “point” and not so much on “counterpoint.” After your readers read your thesis, they should have a crystal-clear idea of what they're going to encounter in the rest of the essay.
In order to make things clear, you can list your three main points—the topics of the three supporting paragraphs—in your thesis. Be aware that to some readers this doesn't look super-sophisticated. As an alternative, you can have an "umbrella" thesis: one overarching claim that accommodates the three or four points to come. Yep, you can write under an umbrella… ella… ella… ay… ay…
Doris and Mortimer are writing persuasive essays about the value of raccoons. (The instructor who assigned the essay is a strange man with a monumental 'stache who wears clothing made exclusively from animal fur.)
Doris misses the mark here; she states obvious facts that would inspire neither curiosity nor debate. She doesn't make a strong point, and she fails to preview the support for her point. Mortimer, on the other hand, nails it.
Doris's Painfully Horrible Example:
Raccoons are hella good swimmers sometimes and eat dog food too.
Mortimer's Astonishingly Good Example:
Raccoons are the best creature in the animal kingdom because of their natural beauty, because of their documented heroism saving babies from house fires, and because of the therapeutic effects of a sustained raccoon cuddle.