So i just finished taking the ASTB a couple hours ago and thought I would share a little since this advice I found here certainly helped me out a lot. I only took the OAR portion, so sorry I cant help the wannabe pilots.
I was always fairly strong in math/physics, but havent taken any classes in those subjects in like 6 years, so I took EVERY practice test I could find. do a quick AW search and you will find 3-4.
Most of the math problems are things anyone should know how to do, the catch is you have to know how to do them quickly. Make sure when you take your practice tests, you time yourself. I managed to finish every section with a couple minutes left and it's all because I got good at pacing myself. Get good at translating a word problem into an alegbra problem. brush up on basic properites of right triangles.
the mechanical comprehension was what I studied the most for. Timing is especially important here because you only get 30 seconds/question. That said, most of the questions are such that if you know what you are looking for, you can solve them without having to do any substantial calculatins. The best advice I can give about this section is go to
www.howstuffworks.com and look up series/parallel circuits, levers, gears, pulleys and 4 stroke engines. They provide great explanations for it all and that stuff will make up 80% of the test. Don't get intimidated by complicated figures - if you approach them calmly you will realize they can be broken down into things you have seen before.
Surprisingly, the reading comprehension is what gave me the most trouble. It's not that it is that hard, but a lot of it seems pretty poorly written. Rather than picking the best response, a lot of times I felt I was picking the least crappy response. There isn't too much you can do about these except take some practice tests and get used to crappy writing.
For what it is worth, I got a 64 and hopefully that is good enough for SWO.
I probably wont be checking back on this thread, so feel free to PM me with any questions.
as for books, unless you are really weak on a ubject, you can probably get everything you need free on the internet. besides the famous marinegouge, there is also the petersons books (search AW). I know it has been said before, but the Cliffs book SUCKS! Do not buy it or look at it! I got it when i first decided to apply to OCS and it was a waste of money. it is full of incorrect answers as well as poor explanations of things you do not need to know for the test
