souvilibra -
With just a few weeks to your exam date, focusing on "tactics" to improve your Verbal score is definitely the way to go. As I mentioned in my earlier post, re-orienting yourself in how you read the RC passages will provide the biggest bang for your buck here. Instead of reading the passage for details (like we do in school or at work), we need to read the RC passage at more of an overview level since the test makers do not expect us to be subjet matter experts. What reading at the overview level really means is to get from your initial reading what the topic of the passage is about, what the author is saying about the topic and how the passage is organized. If it helps you to take notes while reading (and does not disrupt your concentration or slow you down significantly) feel free to do so. But, understand that you will be delving back into the passage on the detail questions and this is where understanding how the organization of the passage truly helps.
Your tactic of pre-thinking on the CR questions is good. But for this to be of siginificant benefit, you must really understand the structure of the argument being presented. By this, I mean you need to determine whether the CR question is requiring you to strenghten, weaken, make an inference, decide which assumption is correct, etc. The GMAT uses a very mechanical approach to logic and, for me, it helps to visualize the structure in some fashion. FOr example, if you think of a strengthen type question as two roads connected by a bridge with the one road being a premise (or several premises) and the other road being the conclusion, the correct answer will be the answer that connects the two roads with no gaps. The primary skill you will need to hone using this tactic will be to be able to idenitify the premises and conclusions in the stimuli. If the stimulus has a conclusion, then you are looking at a strengthen, weake or assumption type question. If the stimulus does not have a conclusion, then you have an inference question (and with these questions, the correct answer is the one that is true 100% - not 99.9% or 98%, but 100% of the time).
With the SC questions, your best bet is tio use reasoning as extensively as possible. While you need to have a good grammar ans sentence construction base, you really do not need to be a grammarian to do well on these questions. People are generally good at determining if a sentence just does not seem "right". Since the answer choices are part of the question, you can weigh and measure the differences in the answer choices to eliminate wrong answers. For example, by reading the initial sentence you realize that it is incorrect because the verb have should be has. You can now go through the answer choices and eliminate any of the choices using "have". For the remaining choices, you can then read to determine the differences in those and eliminate choices that have other errors.
Finally, you mentioned that your lack of improvement on the SC questions, but noted that these were mostly at the back end of the question bank. I would suggest that you review those you missed and figure out why you missed the questions. If there are re-curring themes, you can focus on several and lock those down. If you would like clarification on any of the items I mention above, let me know.