The SAT College Board website declares that every student or instructor seems to have a different opinion on how to earn a high score on the SAT essay:
Some people say you should write a strict five-paragraph essay... Some people say you should read well-known books like The Great Gatsby or The Scarlet Letter and refer to them as often as you can.
The College Board further states that, "We want students to know that there are no shortcuts to success on the SAT essay." The College Board advises that scoring highly is not a matter of what books or materials you have read in the past, but rather how well you can write in the present. What the SAT College Board is looking for in the essay writing section is whether or not you can prove a point, required by a prompt, clearly, concisely, and effectively. The College Board is testing your ability to express your personal point of view in a logical, coherent, and grammatical fashion. They are more concerned with whether or not you can build an argument, using clearly expressed examples, and carry them out to the point that they actually prove your idea, then they are concerned about what you have read. According to the College Board, the only real thing you have to worry about reading is the entire directions to the writing prompt.
However, that being said, since you will need to be drawing on examples, of course expanding your mind with more literature will give you more ideas with which to work with and use to illustrate your arguments. Shorter books or short stories will especially be helpful because they are faster to read. One excellent suggestion is a short novel by Henry James, Washington Square. James is known for his very involved, very complex sentence structure. He very frequently likes to make use of the periodic sentence, which builds on a point using suspended syntax and climaxes in the final word. One example of his sentences is:
He was a thoroughly honest man--honest in a degree of which he had perhaps lacked the opportunity to give the complete measure; and, putting aside the great good-nature of the circle in which he practised, which was rather fond of boasting that it possessed the "brightest" doctor in the country, he daily justified his claim to the talents attributed to him by the popular voice.
Reading and understanding complex sentences like this will not only give you ideas to illustrate your points with, it will also fine-tune your sense and grasp of both grammar and logic.
Reading books with strong themes will also increase the number of insights you currently hold and give you more examples to use. The short story "The Hunger Artist," by Franz Kafka, will give you themes to ponder, such as the feeling of alienation, the desire for religion or spiritual understanding, and also adapting to cultural changes. You can also consider reading Thomas Mann's celebrated novella, Death in Venice, for a theme dealing with a literary artist who separates himself from society for the sake of creating his literature.
The best resource that you can use is the College Board Website itself. It has sample essay topics and sample essays. The essays that thy have as models should be studied to see the characteristics of good writing that the College Board is looking for. If you look at the sample essays you will notice that the introductions are almost always three sentences long and the conclusions are mostly two sentences long.
The introductions have an attention-getting statement, background information, and a thesis. The conclusions all have a general purpose of the question and a final dramatic statement. A mere summary is never a good conclusion. Most of the essays for the body have two paragraphs. One is for the experience you had, the other is for the lessons you learned. Or if you read a book, what the book's importance to the question is, and the other paragraph is for why the author wrote it.
To take up time with examples that are nort really examples but are the exceptions to everything, and they are used as the standard bearer of weak essays: Helen Keller, Einstein, Edison, WW1, WW2, etc. If you don't know anything about these that are not a topical encyclopedia answer, then don't use them. Especially with "Gone With The Wind". Remember that the essay is merely a draft, but you do have to fill two pages. Write what you know, and one piece of advice, do not read the question in the box. It is used to distract you. Read the question that is under the box.