Look on the bright side. Now you know what to expect and what to work on. The ARCO book is apparently good gouge. I didn't use it, but I've heard great things. Also, sit down and scribble down as much as you can remember about the ASTB. Types of math problems, mechanical problems, aviation questions that you remember, etc. Do it now while it's fresh in your mind. Analyze the shit out of the test. Once you've done that, study/practice those types of questions. If you remember it having a lot of math word problems on there, practice the shit out of word problems. Use that ARCO book, get SAT/SAT II math books, seek help from professors, whatever it takes.
Another little piece of advice that is rarely given out: take as many practice tests as you can. They don't have to be ASTB practice tests. SAT, SAT II, ACT, GRE, whatever. Even if the subject matter doesn't exactly correlate, you will get better at taking standardized tests. It's an acquired skill, just like anything else. There are also some 'techniques' for taking standardized tests that you can find online or in test prep courses. For example, if I don't know how to solve a math problem within the first five to ten seconds of reading the problem, I'll move on to the next question. I'll bang out the easier problems (which are usually worth the same number of points) and then come back to the difficult ones if I have time. There's no sense in sitting on question 3 of 25 for ten minutes if I only have 25 minutes to complete the section, right? There are tons of little tips and tricks like that out there, so get your Google-fu on.
Happy studying.
Another little piece of advice that is rarely given out: take as many practice tests as you can. They don't have to be ASTB practice tests. SAT, SAT II, ACT, GRE, whatever. Even if the subject matter doesn't exactly correlate, you will get better at taking standardized tests. It's an acquired skill, just like anything else. There are also some 'techniques' for taking standardized tests that you can find online or in test prep courses. For example, if I don't know how to solve a math problem within the first five to ten seconds of reading the problem, I'll move on to the next question. I'll bang out the easier problems (which are usually worth the same number of points) and then come back to the difficult ones if I have time. There's no sense in sitting on question 3 of 25 for ten minutes if I only have 25 minutes to complete the section, right? There are tons of little tips and tricks like that out there, so get your Google-fu on.
Happy studying.