The best thing to do is try to find your weaknesses. If you think you're weak in mathematics, jump on http://www.khanacademy.org/ and take an algebra or geometry course. English and science is available through the same resource. They do great work there, and it's free of charge. That will take care of a lot of your "normal" subjects. You can even take practice ACT or SAT tests if you want to be thorough, but I found them more difficult personally than I found the ASVAB. If you think you might need help on the more technical aspects of the test like mechanics and electronics, you can use study materials from all sorts of sites specifically tailored to ASVAB prep.
Remember, you're competing only against other people looking to enlist. A lot of those people aren't doing any preparation, so you even asking the question is a great sign that you're willing to put in the effort to stand out. Good luck!
Mitchell recommends the following next steps:
To prepare, you want to find a study book or on-line resource. It's been a while since I looked at it, but it used to include Electronics and other subjects beyond just the basics. They would use your scores on certain tests to determine your eligibility for certain career paths. For example, Electronics might not count if you were trying to get into the Legal field. Give yourself time to study every day, and periodically re-test, using a different test than one you already took! The recruiters also have test preparation guidelines. You do not need to stick with just ASVAB study material. For example, you could also look at GED or SAT study material. But it's important to know what areas you need to study! If you have problems with vocabulary, I strongly recommend good ole fashion flashcards.
If you have passing scores in everything, but you want to bring them up, you need to know which tests will be included for the career field you want. You need to talk to a recruiter. I sometimes choose to concentrate on my strengths, rather than my weaknesses. It just sort of depends on where I am at and how much I need to improve.
When you take the test, all the regular rules apply: Get a good night's sleep, eat breakfast, etc.
Now, this is where I help you get the extra points. The objective is to do the best you possibly can, without cheating. So, you need to find out whether or not they penalize you for guessing. That is, do they take off a fraction of a point for wrong answers, or only score what you get right. If they still do not penalize you for guessing, here is how to "guess" and come out ahead.
When I walk in to take a multiple choice test, I have a letter in my head. Today, it is "C." So, if I encounter a question I do not know, and cannot narrow down whatsoever through the process of elimination, I will put C. If I do this on ten questions, odds are 2-3 of them will be correct. If I just guess willy-nilly, I will likely miss them all. When I get close to running out of time, I will mark all remaining answers with a C. Again, odds are, some will be correct. Let me know if you need further explanation of this.
Now, what if I can narrow it down? Perhaps it is either A or C? or A or D? On these, I just choose the letter closest to the beginning of the alphabet. These two tips will reduce the stress factor big-time! And help you pick up a few extra points. It is NOT a substitute for proper preparation.
I helped a relative to prepare for his third attempt at the test. His score increased so much over the first two times that they made him retake it and fingerprinted him! And yes, he did good again!
Good luck to you!
First and foremost, Dont rush. IT is a timed test, answer the best you can. IT is basic math and enlish skills, the better you do, better the job you can get. I got a pretty good score and was able to attend school for a year, then over the years I ended up at Dell for 19 years.
As a veteran, and a horrible test take...
Study, do practice tests online and in the book, research what scores you need for the career you are most interested in and set a goal of when you want to take your ASVAB. Taking the ASVAB is on your time, be as ready as possible and do your best.
Remember that you can retake this test if you are not satisfied for the results.
Best of luck!