Just took the OAR for a second time yesterday and I improved my score from a 47 to a 57! I'm definitely happy about that score and i'll be keeping it. A little about myself: I have a BS in Poly Sci from UCF (3.9 GPA) and Masters in International Affairs: Security and Intel major from the University of Pittsburgh (3.8 GPA). I am applying for Intel but considering IW and SWO also. While my GPA's are solid a 47 is meh, so my recruiter thought I would be better served by retaking and i'm glad that I did. Here is a breakdown of my experiences with the test:
Math: I'm not a math person so this is where most of my studying time was spent. The best advice I have is to use the gouge posted here. Go back through at least the last 100 pages of this thread and read/work through the problems posted by people. I guarantee you stand a good chance of seeing some of them on your test. I saw at least three and it definitely helped. I had a ton of word problems so I can't remember specifics but I saw things such as adding square roots, a car depreciates in value 10 % a year what is its value after 3 years, high level factoring including negative exponents, averaging test numbers but the tests had different weights associated with them, and a matrix multiplication problem. The first time I took the test I saw none of this. I knew I was doing well because the math was exponentially harder this second go around.
Use the study guides others have made, they are life savers. Use the ARCO book, Peterson's, Khan Academy videos, and GRE math books. Work through every practice test you can get your hands on and after those use GRE practice tests (it's not the same, but the problems are closer to the difficulty of the OAR problems.) I would stay away from the Accepted Inc. and Mometrix math, they are just way to simplistic.
Reading: pretty straightforward as others have said. Really boring, dry passages that you really have to concentrate on. I found myself reading them aloud just so I could stay focused on their content. My best advice here is to manage your time well. Don't get bogged down on one problem because you will regret it later as the time starts narrowing down. Eliminate answers you know to be wrong and make an educated guess if you can't decipher the right answer. Stay focused and you will do fine.
Mech: I only lasted about 7 minutes in this section before the computer ended my test. Mostly conceptual questions but I did have to compute some basic math. I saw pulleys, a circuit with a switch, heat transfer with conductivity, a pendulum problem, and kinetic energy. But I also had to find the weight of somebody on mars with their weight in kg and different measurement of gravity given to me, and I had to know the formula for work.
Overall: Study the gouge posted here. I credit finding this site for my improvement. Start studying weeks before the test, don't cram. I started studying off and on five weeks ago. Take the test "strategically" and by this I mean don't spend an overwhelming amount of time on one problem. Some guessing will almost naturally be involved just make sure to eliminate some wrong answers ahead of time. I think this was my problem the first go around. I let the timed aspect get to me, I spent too much time on a few problems, and ended up blindly guessing towards the end. If you can avoid doing this, you will improve your scores.
Good luck everyone!