1. A thesis statement…
tells the reader how you will interpret the significance of the subject matter under discussion.
is a road map for the paper; in other words, it tells the reader what to expect from the rest of the paper – you must subtly expose the trajectory of the essay here.
directly answers the question asked of you. A thesis is an interpretation of a question or subject, not the subject itself. The subject, or topic, of an essay might be ignorance or faith; a thesis must then offer a way to understand the words from a unique perspective.
makes a claim that others might dispute.
is usually one or two sentences towards the end of the first paragraph that presents your argument to the reader. The rest of the paper, the body of the essay, gathers and organizes evidence that will persuade the reader of the logic of your interpretation.

2. Things NOT to do in an introductory paragraph:
Apologize. Never suggest that you don't know what you're talking about or that you're not enough of an expert in this matter that your opinion would matter. Your reader will quickly turn to something else. Avoid phrases like the following:
In my [humble] opinion . . .
I'm not sure about this, but . . .
Announce your intentions. Do not flatly announce what you are about to do in an essay.
In this paper I will . . .
The purpose of this essay is to . . .
Get into the topic and let your reader perceive your purpose in the topic sentence of your beginning paragraph.
Use a dictionary or encyclopedia definition.
According to Merriam-Webster's WWWebster Dictionary, a widget is . . .
Although definitions are extremely useful and it might serve your purpose to devise your own definition(s) later in the essay, you want to avoid using this hackneyed beginning to an essay.
Dilly-dally. Get to it. Move confidently into your essay. Many writers find it useful to write a warm-up paragraph (or two, even) to get them into the essay, to sharpen their own idea of what they're up to, and then they go back and delete the running start.

3. Rather, do this in your intro:
Begin with a strong hook – really make your readers hungry to continue reading your essay
Brief anecdote
Surprising fact
Quotation
Humor
Well-developed central idea – build up to the “big idea” of your thesis statement
Provide some background information to continue to whet the reader’s intellectual appetite
You have one paragraph to procure the essay’s success – don’t blow it.
Clear, sophisticated, specific thesis statement (see first slide)
Everything in your introduction must clearly introduce the subject of the essay and not appear to be irrelevant to that subject.
Your intro paragraph must establish a pronounced tone – an attitude – that loads your language with as much connotation as the words’ denotation already signifies.