Enroll in GED preparation classes at a local community college or night school. There are two different sections in most states, one for people under 18 and one for people over 18. Remember to bring a form of identification and a parental approval form when you sign up for classes.
Work on both your reading and writing skills. You must be able to analyze sentence structure and write a short essay on a general topic to pass the GED. Practice writing essays within a 45-minute time limit because that's how long you'll have on the actual exam.
Review some basic United States history and practice answering questions following a short reading. The social studies portion of the exam will focus more on reading comprehension than it does on historical facts, but you may also have to extract information from charts and graphs.
Study general science concepts like photosynthesis, energy and simple chemistry. Learn how to read common scientific charts to help you prepare for the GED exam. Familiarize yourself with basic science vocabulary, because you may have to respond to questions after reading a short passage.
Practice your math skills and be sure that you understand geometry, algebra and simple data analysis. Learn how to perform basic operations without a calculator, since you don't get to use one for the first part of the test.
Ask your GED preparation teacher for a sample copy of the exam. Take the test within the same time limits that you'll have during the real exam. Review your answers with the teacher to find out what subjects you need to study.
Find out how your state handles the grading of the GED exam. In some areas, you can only retake certain sections a few times each year and some of your scores will carry over from test to test. Ask if your state requires a score of 410 out of 800 for a passing mark on each portion of the test.