Hi pacer,
Exactly how you review your practice tests is, to a degree, a matter of personal preference. Here's how I do it:
Upon completion of the test, I immediately check my answers against the credited responses. I want to see what my score is, obviously. On my booklet, I mark the questions I got wrong, but do NOT notate the correct answer choice. A few hours (or a day) later, I would return to the practice test and re-engage the questions I got wrong. The goal is to arrive at the correct answer choice on my own, without being biased by "knowing" what the answer is. Obviously, you know that you got the question wrong, so whatever answer you picked the first time around is incorrect. Still, it's an incredibly useful exercise.
After I'm done, I double-check my answers against the credited responses and analyze all mistakes I made. I try to understand the line of reasoning that led me in the wrong direction. I also focus on the type of “decoy” answer I chose, and make a point not to repeat the same mistake again. Although no two LSATs are exactly the same, there is an incredibly high level of consistency between the tests. It is imperative to use this consistency to your advantage—avoid making the same mistake twice and your score will improve.
Additionally, I'd also focus on any questions that took too long to solve, even if I ultimately got them right. As I take each practice test, I “flag” any question that took more than 1:30—2:00 min. That way, I can easily return to these questions during your test review. Whether I answered the question correctly is irrelevant: if it took 3 minutes to figure out, clearly there is a problem that needs fixing.
I also suggest creating a Word document or an Excel spreadsheet listing every mistake you make. Identify the type of question missed and explain, in a few sentences, what made you choose the wrong answer. E.g.:
December 2006, LR 1, Q1: Main. The correct answer is (D), I chose (A). Chose the opposite answer because I failed to differentiate between competing viewpoints. In the future, pay attention to competing viewpoints in Main Point questions.
Does that make sense? Let me know.
Thanks!