Hi tycoon_316,
Firstly, you are absolutely correct in your self-assessment. Your Quant is great and therefore, I believe you have the potential to get a 720 and above.
I do agree with you that on the actual GMAT, I did receive a very hard RC passage. It was short, but extremely tough to follow. It was one paragraph with maybe 3 sentences. One of the sentences was more than half the passage - very, very confusing. I am by no means going to pretend to be an expert on RC, however, I did improve immensely towards the end of my studying. At some point, it kind of just clicked and I knew what to look for when reading a passage and what traps to avoid on the questions. With respect to study materials, use OG and Verbal OG for Reading Comprehension.
In terms of RC strategy, all I can recommend is what worked for me. Please note that books and other people completely disagree with what I'm about to say. My strategy is to read the passage once quite thoroughly - reread parts when you don't understand something. However, I suggest not taking a lot of notes - this wastes way too much time. Make sure you understand why the author is writing and the main idea of the passage. You do not need to memorize details - just know where they are in the passage. For each question, go back to the passage and re-read the relevant paragraphs once, twice, even three times. Then, go with a "non-strong" answer. Avoid words of certainty like all, always, and definite. Those are usually traps and can be eliminated as answers quite easily. I learned this with practice, not from a book. In studying, do a ton of RC, but don't give yourself a time limit. Practice without the stress of the clock and learn why some answers are wrong, and why some are right. Up your percentage of correct RC answers without a clock, and then figure out how to do better when you are timed. They key is to do a lot of problems, but do them critically and try not to make the same types of mistakes. Also, whenever you read the solutions, read why each answer choice was wrong. Patterns will reveal themselves and will start to notice them when evaluating an answer choice.
With respect to SC, which was also my weakest area, I think I have come up with a decent strategy (at least one that worked for me). It does depend on whether you are an English speaker or not. If you are not (or English is not your first language), I do not think my strategy will work. Basically, Manhattan SC 2007 is a great book, but it is very difficult to consider all its information on each SC question. So, I came up with my top 3 things to look for: (1) Subject-verb agreement, (2) Pronoun-antecedent agreement, (3) Sentence parallelism. I would find sentences that are correct according to those categories, and if I was left with a couple of options (typically due to verb tense), I would ask myself, "Which one sounds right?" As an English speaker, your ear is typically able to pick up the correct verb tense and whether a sentence is sufficiently concise. If you are a non-English speaker, I would suggest reading the Manhattan SC book at least 5 times. I would focus on memorizing all the rules and learning how to form the best sentence. This will take a ton of work, but in the end, I think it is the only way for a non-English speaker to learn all the rules.
All-in-all, for RC, I would suggest practice, practice, practice. For SC, choose the key Manhattan rules, then "'listen" for the sentence that sounds best (unless you are a non-English speaker). Definitely buy Verbal OG and note that the problems at the end of the book are the hardest.
All the best in your studying, and please do not hesitate to ask more questions.
-mgross