It *can* be okay to guess on a complete RC passage, but if you're going for a 700+ score, then I don't suggest that you automatically assume that you will do this. Decide to do this only because you get a nightmare passage. During the test, it might turn out to be the case that you get some nightmare CRs or SCs instead, and then those are the ones you should skip.
One other thing for a night mare passage: you may decide that you're going to try the main idea question but leave the rest. You don't need the whole passage for the main idea - just the big picture stuff.
Re: freebies, generally speaking, you should guess immediately if you get a nightmare (for you) question, period. That only saves you about 1 to 2 min (depending on question type), so there is no real impact to your overall time management, as you only need to take action if you are more than 3 minutes off of your expected time. It will all balance out.
I tell people to track freebies mostly because this gives them "permission" to go ahead and guess immediately / randomly. Otherwise, I find that people tend to hesitate / not want to just let go, even when they really should. As a general rule, the upper limit for a Q or V section is 7 freebies, though if you are looking for a score of 49+ on quant or 39+ on verbal, then I'd limit it to 5.
(Note: a freebie means that you guess randomly and move on. It doesn't apply when you've narrowed down answers - then, you've actually improved your odds / it's a legitimate answer.)
I tend to spend more time on Tough RC and get all the answers wrong.
What is the rational response to this situation? What if I said to you: "I tend to invest more of my retirement account in super-risky stocks, and I tend to lose money." What should I do?
Stop doing that in the first place! Stop trying to answer the hardest (for you) questions. Get your points someplace else. If you know, for example, that you can usually handle main idea and specific detail, but that all inference questions are your nemesis, then start making those your freebies. If you know you can handle inference on a business passage but not on a science passage, then make science-inference your freebies. Basically, know your own strengths and weaknesses and react accordingly.
I think a lot before writing a sentence now. I always feel that that there is something wrong in the sentence when I write . To my dismay , this feeling is at its worst form when I write AWA
Yes, this is not unusual. First of all, the AWA is impromptu, and the test writers make allowances for errors for this reason. Everyone would write a better essay if they could put it away for 24 hours and then re-read it. Further, the test writers will know if you are a non-native speaker, and they make even more allowances for that. The quality of your ideas matters more than the quality of your grammar and spelling. (If the grammar and spelling are so poor that people can't understand your ideas...then that's a problem. But if your ideas are coming across, you will be okay, even if the grammar and spelling aren't stellar.)
Finally, in terms of the GMATPrep questions (and practicing RC in general): how are you trying to learn from those questions after you're done? Are you doing this:
http://tinyurl.com/2ndlevelofgmatIf not, start using the 10 questions (you'll understand when you read the article). And always remember that the goal is not to learn how to do everything. The goal is to learn:
(1) how to get *some* things right, and
(2) how to know when something is too hard for you, so that you can let it go before wasting too much time and mental energy on it