http://http://www.columbia.edu/~mmx1/astb/
Go to the ASTB forums on this site. There is a wealth of information there.
That link has been dead for years.
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As said, most of the stuff is common sense, and there will be a couple that you will probably guess on as you likely have never seen them before.
Know physics in relation to airplanes more so than your intro to physics class. I.e. know about pressure above and below flight surfaces. It's been a year since I had taken the exam, but that is the gist of it. I studied the Arco and Barron's books, as well as the Marine pdf's. In Barron's I did the AFAST problems too for extra practice. -It depends on how good you are at physics and how much time you have to prepare. I had ~ 1month to study and scored 7,7,8 58. And I only took one version, FYI.
In short, study as much as you can to cover a wide variety of problems. Focus on your weaknesses. And don't neglect other sections unless they are your strengths and Mechanical is your weakness. (Redundant, I know
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As far as tool knowledge, I don't remember, but I think there weren't any of the questions about tools like there were in Arco or Barrons. Just simple tools at most: levers, wedges, pulleys. Again, though, I took version 5 only.