It might help to look over one of the tests like GR8677 or GR9277, just to see where you are at. I started from scratch about a year ago and took GR9677 around March earlier this year. I managed to get four
questions right, all of them having to do with electromagnetic induction. I even got the one with the spin up of the torsion rod with two charged pith balls at the end right, since it was a problem in Purcell. Unfortunately, I understood NOTHING about any of the other problems. About six months later, and with a s**t load of work, I managed to get in the 54% percentile on the GR0177 form. After spending $130, I took the real test on Oct. 18. The proctor was an hour late and I could have stabbed him with my three nicely sharpened pencils. I got a 750 (66%) on that test. In retrospect, if I had realized that when two space men kick a ship simultaneously in their frame of reference, it does not mean that the events happen simultaneously in the reference frame of the ship, then I could have gotten one more question right.
ETS also has some Major Field Test thing, which is like the GRE except with fewer questions. You can find it here:http://www.ets.org/portal/site/ets/menu ... f95190RCRD
The questions are similar to the GRE just in case you didn't want to "corrupt" the practice tests that you have.