Determine which areas you think may be difficult for you. Concentrate on those areas first.
Take the self-assessment module quizzes found at the Test Prep Review website (See below). Try taking the quizzes even in areas where you don't feel you need help; this will expose you to all the types of questions found on the ACT exam and will help you pass it.
Utilize ACT exam study guides. Some can be found online, and some are available in libraries or bookstores.
Enroll in an ACT classroom course or online course, if necessary. Most sessions last six weeks.
Find a private or group tutor in your area, if a classroom setting is not for you and you do not have access to a computer. Most will find a small group of friends learning together works best for them.
Get plenty of sleep the night before the test. It is important to be mentally alert and well rested; you will be more likely to pass the ACT then.