The best, but not necessarily the easiest way to "pass" an aptitude test is the same way to pass any test: study, study and study. Most aptitude tests are not pass-fail, but rather they test your aptitude on a variety of subjects. Scoring very low is considered bad, but not necessarily failing.
Aptitude tests are a type of standardized testing that includes the SAT, ACT, GRE, LSAT and ASVAB, among others. They test your aptitude in a number of different subjects to gauge your preparedness for whatever lies in your future path. In some cases, that could be college, graduate school, law school or the military.
These tests are designed to ensure you have an active, working knowledge of things that you may encounter or be tested on while engaging in this new venture. For instance, the ACT test records your abilities in English, mathematics, reading, science and writing. This test is recommended for students about to become undergraduates in college. Most undergraduate students must take at least one composition class, math class and science class. Taking the ACT or SAT test gives them an idea of what they will be dealing with while in college. It also gives prospective colleges an idea of the aptitude of the student and can sometimes determine what entry level classes they are placed in.