A thesis statement has to succinctly describe the overall topic in one sentence. Suitable topics are typically a niche of an overall subject. For example, in an essay about world hunger, a possible thesis statement would advocate or discourage the application of a specific solution within an impoverished country. However, the statement cannot be too specific or purely factual; it has to leave a certain room for error and doubt which the essay will address.
A thesis statement functions as a transition from a general overview of the topic to the specific content in the essay. To do this, the statement should describe the overall logical flow of the following body paragraphs. The typical structure of a thesis statement is that it first states the main point of the essay followed by main reason on why this point is correct. For example, the thesis statement "Democracy works in the United States because of the benefits of capitalism" works because the essay's direction is clear from the statement.
Ultimately, a thesis statement has to grab the attention of the reader. The reader has to feel the necessity to read through the author's further explanation of main points. The topic has to generate interest by itself; it can relate to a controversy, a debate or a new, uncommon perspective on the overall subject. Additionally, the statement has to reflect the author's true opinion on topic; a statement becomes far less relevant if the writing of the author doesn't show conviction. It has to be as informative or aggressive as the author herself believes to be accurate.
For many writers, the thesis statement is the most difficult part to write in an entire essay. This is because they are often unclear about their position or depending too heavily on their research. For example, writing a thesis statement as a question reflects the author's uncertainty over the essay; while a question may invoke thought and interest, the essay should start by providing the process towards the answer, not the question itself. Additionally, the author might try to be too confrontational in the thesis statement due to the strength of his research. No matter how obvious a topic may seem, the discussion should still take place in a logical manner to gradually prove the point.