Study mathematics. A large portion of your IQ score comes from exams that test your math and spacial reasoning abilities. For example, you may have to answer word problems that ask you to solve a problem based on the information given. By studying math--in school or on your own--you can learn how to solve these types of problems.
Improve your vocabulary. IQ tests may use high-level vocabulary words and if you don't understand what the words mean, you won't be able to get the question right. While there is no special list of vocabulary words you should know for an IQ test, you can use the list for the SAT or ACT exam. Create flash cards to review words or purchase a word-a-day calendar.
Learn something new. Find something that interests you--such as learning a new language or how to knit--and study it. When you learn a new skill, your brain stays active, which can make you do better on IQ tests.
Eat before the exam. Part of doing well on IQ tests is having the concentration to work through the problems. If you are hungry, you'll be distracted and are more likely to do poorly.
Take IQ tests regularly. Familiarity with the exam and the types of questions you'll encounter can help you to improve your score on an IQ test. It also helps you to exercise your mental muscles as you work out the problems.