Use a reasonably-sized font: either 10 characters per inch or a 12 point font. And choose a font that is easy to read rather one that is decorative: "Arial," "Lucida," "Modern," "Palermo" or "Times New Roman" are some good choices. Scripted fonts are hard to read even if they do make your paper "look nice"; it is the content of the paper that is most important, and making it easy for your readers to understand that content is always a good choice.
The introduction serves to inform the reader of the basic premises, and then to state the author's thesis , or central idea. A thesis can also be used to point out the subject of each body paragraph. When a thesis essay is applied to this format, the first paragraph typically consists of a narrative hook , followed by a sentence that introduces the general theme, then another sentence narrowing the focus of the one previous. (If the author is using this format for a text-based thesis, then a sentence quoting the text, supporting the essay-writer's claim, would typically go here, along with the name of the text and the name of the author. Example: "In the book Night , Elie Wiesel says..."). After this, the author narrows the discussion of the topic by stating or identifying a problem. Often, an organizational sentence is used here to describe the layout of the paper. Finally, the last sentence of the first paragraph of such an essay would state the thesis the author is trying to prove.  The thesis is often linked to a "road map" for the essay, which is basically an embedded outline stating precisely what the three body paragraphs will address and giving the items in the order of the presentation. Not to be confused with an organizational sentence, a thesis merely states "The book Night follows Elie Wiesel's journey from innocence to experience," while an organizational sentence directly states the structure and order of the essay. Basically, the thesis statement should be proven throughout the essay. In each of the three body paragraphs one idea (evidence/fact/etc.) that supports thesis statement is discussed. And in the conclusion everything is analyzed and summed up. 
A good definition essay is required to have a strong thesis statement in which the point of view of the author on a certain term is revealed. Ordinarily, the term is given the general basic definition implying that the dictionary definitions must be only a start for the author’s unique definition of the term. In order to make a definition essay professionally it is necessary to find a definition of the term that corresponds to the opinion of the author. The definition is always given in own words and specifies what meaning of the term is to be analyzed.