Aimba123 Don't worry about the pace issue, the reason I say that is because almost everybody will struggle with their pacing on the GMAT. Even when I do really well, I am always on my toes, so this whole situation of constantly being stressed and rushed is part of the game. That is not to say that there aren't people who do extremely well with say 15 minutes left. I have had a fair number of students in that category, but I would say 98% of us will always be under tremendous pressure.
As far as guessing on some of the questions, that is common too, I think the key is to steer away from the hard questions that won't impact your score much, and instead can be time sinks. May be two or three that you can sidestep.
In my personal opinion, cookbook strategies don't really work on the GMAT, unless you are lucky and see the exact same problem in the exam. That is rare. Instead of trying to look for what would work where, I would recommend you to deeply understand what the question is asking, without making any assumptions and approach it with general tools as opposed to trying to fit a preexisting method.
I don't teach the Verbal section of the GMAT, but I can tell you that on the RC I recommend reading the passages with deep focus. This is not easy because the GMAT passages are extremely dense. This one will take practice to improve. You may first want to deal with easier passages and then raise the difficulty level. I found the categorization and the explanation in
the official guide to be extremely helpful.
I would skip the tests from Barron's. Instead, take the second test in GMATPrep and then dive in to the set of questions in the forum link I posted earlier. you could get the Exam Pack 1 extension that gives you two more CATs, but at this stage I don't know if taking a lot of CATs will help. You need to strengthen your conceptual understanding, once you do that it also helps with the pacing.
Cheers,
Dabral