The ASVAB, or Armed Services Vocational Aptitude Battery, is a test administered by military recruiters which measures your knowledge and critical thinking in math, science, verbal, technology and spatial reasoning. The subtest consisting of the math and verbal sections is called the Armed Forces Qualifying Test, or AFQT, and your scores on this portion determine which branch of the military you are eligible to join. Practice testing, targeted review and knowledge of test-taking strategies can help you score high on the ASVAB.
Obtain full-length practice tests and a timer so that you can test yourself at home under conditions similar to a real test. The ASVAB comes in three formats: the computer adaptive version, the paper-based version given at a mobile exam test site and the paper-based student test given in high school. Try the different versions to see how you perform best. Do practice sets under timed conditions once you build up your confidence. The paper-based ASVAB gives you less than a minute per question on average, and the computer adaptive version gives you only a bit more.
Review arithmetic, algebra and geometry. In particular, you should practice doing mental math. Since calculators are not allowed on the arithmetic or mathematics knowledge sections, you will need to be comfortable doing calculations in your head or on a piece of paper. Look over vocabulary lists and make flash cards for the verbal sections. An SAT vocabulary study guide will be helpful for building your vocabulary, as SAT vocabulary is harder than what you'll encounter on the ASVAB.
Don't stress over the science and mechanical portions if you are not seeking a military job in these fields. There is no pressure to "ace" these sections if you are not mechanically or scientifically inclined. Just do your best and focus on the AFQT portion of the ASVAB.
Make sure you answer every question, even if you have to guess. Never leave a question blank. With four choices, you have a 25 percent chance of getting it right if you guess, more if you can eliminate one or two choices.