The first step in studying for the SAT is understanding the format of the test. The SAT contains three sections: writing, math and critical reading; each section contains different types of questions. For example, the math section comprises mainly problem-solving questions testing skills such as arithmetic and algebra. The writing portion includes a timed short essay as well as multiple choice questions on grammar and usage. The critical reading section includes comprehension of sample passages and sentence completion questions.
Passing the SAT without any help is certainly doable, but in order to get the best score you can, get some form of supplemental help. There are many quality SAT study books as well as internet-based and in-person prep classes. Getting a study book or attending a prep class gives you access to important information about the test including common test questions, strategies to use during the test and how to maximize your scoring potential.
Practice answering the types of questions that you'll see on the SAT. Familiarizing yourself with practice SAT questions helps you gain confidence in answering the questions you get when you take the exam. Study books and prep classes should provide you with plenty of practice problems, but you can also find sample problems online for free. For example, College Board offers free sample problems and full practice tests online, as well as the option to sign up to have an SAT "question of the day" emailed to you each day.
Spend a little time each day practicing for the SAT. Reviewing practice questions and test-taking strategies for about half an hour every day between signing up for and taking the test will help you retain more of the information than spending five hours studying the night before the test. The more time you spend practicing before you take the test, the more confident and prepared you will be.