The thesis statement provides focus and purpose to the essay. A strong thesis clearly presents the content to be discussed in as succinct a manner as possible. A bad thesis is too broad and points the audience in multiple directions, which can be confusing to both the audience and the author. Good thesis statements identify a topic narrow enough to be developed in the essay without feeling rushed or too thin. For example, the general topic of the music industry can be narrowed to a specific band or record label.
The introduction is the most important part of the essay. Readers are typically hooked within the first 50 words, and if they are not convinced to keep reading, they won't. The first sentence should grasp the reader's attention. Good openings don't waste time by stating obvious or vague observations, but provide readers with context in a straightforward, engaging manner. The topic sentence gives the theme of the essay -- the "why" of the introduction.
Every good essay needs a structure. Jumpy narratives can be jarring and incomprehensible. Determine the focus of your essay and develop a logical progression of ideas. Present a single idea in each paragraph, and divide sections with subtitles if it helps the logical flow of the essay.
Good essays are written in the active voice. For instance, "I shall always remember my first visit to Boston" is better than "My first visit to Boston will always be remembered by me." Also, stick to using the positive form of statements. Make definitive statements and avoid noncommittal language such as "not" as a means of evasion. For example, "He usually came late" is better than "He was not on time very often."