Study your vocabulary words. There are many books, study aids and websites offering lists of the vocabulary words that appear most frequently on SAT tests. Get a list and start memorizing the words you don't already know.
Learn to focus on what's really important as you read. When you answer passage-based questions, you need to find the pertinent information within the section, determine what it means and use it to correctly answer the question. It is imperative that you quickly identify the information that applies to the question.
Make educated guesses. Practice quickly ruling out the answer choices you know are incorrect. This improves your chances of selecting the right response.
Find a good SAT study guide. Most guides have sample test questions in the same format as those on the actual SAT test, as well as answers so you can see how well you've done. Or, enroll in a SAT prep class. If you learn best in a classroom-type environment, this can be especially beneficial.
Practice answering both types of questions under timed circumstances. The knowledge that you are being timed can add an element of pressure. The more comfortable you are in this situation, the better your performance will be when it's time to take the real SAT.