First I mark my answers wrong without filling in the correct answer, or have someone grade it for me. Then, I attempt the wrong ones again. I go over the right and wrong answers, because sometimes there are questions that I totally guessed on (whether or not I got it right), and I need to know why the answer is what it is. If there is some useful bit of information or some new twist that the testmakers have put into their answer key (I use TBR; there's TONS of those), I take notes. I read front to back, and because their answer keys are so detailed, it takes a few hours. It's well worth it though. I learn so much just from the answers keys alone; it's almost like I don't have to read the books.