Hi Sstern,
Thanks for your important question. Here are some tips for final preparation:
Accuracy
1) Track the question types which you miss with more frequency or consistency, and work on identifying areas for improvement. For instance, if you're often missing assumption questions, are you having difficulty identifying the conclusion, the assumption itself, or making sense of the answer choices? Then work on practicing that particular skill.
2) If you notice that you are sometimes misreading the question stem, try reading it twice (a relatively small time investment) to ensure you follow it correctly.
3) Pay close attention, in both LR and Reading Comp sections, to basic language elements related to quantity, time and likelihood.
Speed
1) Pay attention to your habits in diagramming. If you are frequently exceeding 90 seconds on conditional reasoning questions in which you do diagram, for instance, you may be over-diagramming -- you don't necessarily have time to cover everything you might map out, if it's not essential to answering the question. On the other hand, if you find you spend 30-45 seconds staring at answer choices on those questions, and you are not diagramming, you may be under-diagramming, and could rule out incorrect answers faster with the aid of a quick representation of the logical rule.
2) In general, notice when you are spending an inordinate amount of time on a question. If you are staring at a particular pair of answer choices, it might be true that an extra minute would help you identify the correct option with more confidence (and it might not be), but that investment of time is not generally helpful, unless your pace is otherwise very quick. If speed is at issue in a particular section or at large, limit yourself to 30 seconds or less to deliberate answer choices, once you've read them. You can always star that question and revisit it if time remains.
3) Close reading the first time saves time in the long run -- work on noticing instances where you attach implications or assumptions to a particular passage or stimulus that might be intuitive in the real world, but can not be counted on in the world of the LSAT. You might figure it out after scrutinizing the questions, but it's a time-saver if you're careful not to over-read or skew the material from the beginning.
How do you know that you're adequately prepared?
When you've reviewed and drilled every question type repeatedly, identified problem areas and worked on those more intensively, practiced in both untimed conditions (to focus on careful skills-building) and timed conditions, can transition mentally with some ease between the three LSAT sections, and can stay focused and mentally engaged for up to 4 hours.
How do you know if you're "over-preparing"?
If you find that you are getting increasingly mentally fatigued or losing concentration, or if your stress level is dramatically increasingly, you may actually be testing and practicing too intensively. How much prep is ideal is a very subjective question -- some test-takers do need a lot more time to hit their peak, so I never recommend a particular number of hours or tests, but what I would say is that maintaining a healthy schedule and outlook is to your advantage. "Cramming" isn't necessarily helpful with the LSAT.
What I do recommend as a baseline is that you stay engaged with every section each day, so even on busy days, do a game (at this point in your prep under timed conditions, so aim for less than 10 minutes, even if it's a tough game), a reading comp passage and question set, and around 6 Logical Reasoning questions. Of course, on plenty of days you may be taking timed tests and whole sections anyway, but putting in at least 30 minutes even on the days in between help keeps your "intellectual muscles" flexed and stretched, so that you're always keeping your LSAT skills honed.
Just before the test day, get ample sleep, and have a little fun to release stress (but not the kinds of "fun" -- e.g. getting drunk -- that kill brain cells!). On the day of the test, remember to breathe, eat a healthy breakfast and hydrate, and trust what you've learned.
I also suggest looking at the study plan available here:
http://blog.powerscore.com/lsat/bid/284 ... -2013-Test
Good luck!
Beth