During the year and half that I was going through the WO selection process, I ran into so many people that just didn't do well with their AFAST.

DONT BE CHEAP BUY YOURSELF THE STUDY GUIDE.

I studied with "Learning Express-The Complet Perparation Guide-Military Flight Aptitude Tests 2nd edition"
ISBN-13: 978-1-57685-460-0
ISBN-10: 1-57685-460-4

It cost about $24.95 and if you can't afford it, then go get a library card and get it from the library.

I used the free study guide by ARCO for the AFAST provided at this link.

http://www.petersons.com/army/mfat.asp?sponsor=10

I printed it out and used it for about 2 weeks before I took the test. I scored a 147.
I made it a point to memorize the complex movements key. I also went to another site, something like howthingswork.com, and read up on my general knowledge.

Sadly i found the mechanical portion the hardest cause i delt alot with physics. And unfortunate for me i never took a physics class. Luckily i still carved out a 137 wich isnt to bad in my opinion.