Taking your points in order:
1) For DS, just make sure that part of the problem isn't timing. A lot of people spend more time on PS and rush on DS to make up for it. If you're doing that, then of course you're not going to do as well on DS, especially on DS problems that require a lot of work.
For problems where you need to test cases, draw a quick numberline and label -1, 0, 1. Then make two little marks for fractions between 0 and 1 and fractions between 0 and -1. Then draw little arrows from 1 going to the right (to remind yourself you could try bigger numbers) and from -1 going to the left (to remind yourself that you could try even smaller numbers).
Next, you don't want to try everything - that'll take forever right? Try anything you want first; that'll give you a yes or a no. (The "testing cases" problems are almost always yes/no problems.)
If you get a yes, ask yourself, "What do I think I could try that might give me a no?" If you get a no, try to figure out what will give you a yes. In other words, you're actively trying to *disprove* the statement - because if you get one yes and one no, then the statement is not sufficient.
As soon as you do get 1 yes and 1 no, stop. If you try several things but keep getting the same answer (always yes or always no), then go with it in the moment - but afterwards, check to see whether you can use your growing knowledge of the problem (from trying multiple numbers) to understand the actual theory and answer the question "
Why is this always yes (or always no)?"
Over time, you'll train yourself to use the real numbers to help you start thinking about the actual underlying theory. This will help you in two ways: if the statement is not sufficient, you'll more quickly be able to figure out what kind of number will give you the "opposite" answer when trying to disprove the statement, as discussed above. Alternatively, if hte statement IS sufficient, you'll more often be able to figure out the theory / proof that tells you "I'll always get yes (or I'll always get no) on this one, so this statement is actually sufficient." (But just remember: sometimes you don't actually "get" the theory - so if you've tried 3 or 4 different things, using your number line, and you keep getting the same answer even though you were actively trying to get the opposite answer, then just go ahead and say it's sufficient. If you're wrong, you can learn why afterwards.)
I try solving the problem within 3 mins. If on the other hand, I find the question difficult, and after all working around with the problem I still can't figure out how to eliminate options I make an educated guess by 2 mins or so.
Not terrible, but still too long on both counts. You need to average 2m across the
entire test. If you're spending up to 3m on ones you think you can do and 2m on ones you think are too hard... you're either going to run out of time or you're going to cut yourself off too fast on others and increase the incidence of careless mistakes.
Your actual decision point is around the 1m mark. If you don't know what you're doing by then, and know that you can finish the problem in the next roughly 1 to 1.5m, then figure out how to guess and move on. You can spend up to 2m total making that guess, but on some questions, you do have to finish faster - either because you know how to do the problem or because you guess faster.
It's a bad idea to go beyond 2.5m on quant as a *regular* practice. It's okay to have one or two questions in the entire section that run 2.5 to 3m. But that's it. If you need 2.5+ min, there's already a problem, because every question does have a 2m solution, but you're not finding it.
You mention that quant is consistently 48 to 50. That's good - but you'd rather have it be at the 50 end, not the 48 end, right? That's a difference of 12 percentile points. One of the causes of that fluctuation (though not the only one) is timing - so make it better, solidify that score at 50, and that helps get you closer to 700. :)
For a 50 (90th percentile), you can still probably comfortably get 20% to 25% of the questions wrong (nobody knows for sure exactly - they don't publish that data). Your general pattern here should be: when I know what I'm doing (which means BOTH that I can answer it correctly and I can do so within the normal amount of time, which we'll call up to 2.5m for quant), then I do it without trying to rush to save time, because I don't want to cause a careless mistake. When I can't, I make that call somewhere around the 1m mark (sometimes a little faster if I know it's way out of my league, sometimes a little slower, but still well under 2m, if I think I might be able to... but then realize that, nope, it's not happening). Then I see whether I can make an educated guess, but I also make sure that I have my answer in and I've moved on at or before the 2m mark.
I would ideally like my accuracy to be hovering between 75% and 85% and reduce the errors that I have been committing,
That would mean that you'll be scoring in the 90th+ percentile on verbal. Right now, your score is much lower than that, so you would be talking months here. Also, your overall score is 700 - with your quant score, you do not need to hit 90th percentile on verbal to hit 700 overall. My guess is that, as before, you're not fully comfortable with how the scoring works and so you're setting goals that aren't really the right goals. This is important because that's going to mess up your timing and your approach, both of which will make it harder for you to reach your goal.
Verbal is always going to be your weaker area. Here, you really are going to be going more for the 60% correct overall. If SC is consistently higher, as your strength, then RC and CR don't have to go as high.
a) I tend to spend more time in analyzing the question, sometimes overthinking, and invariably choose the wrong option.
Afterwards, do you go back and analyze both the passage and your thought process to see what led you astray?
b) Find it way too simplistic and rush into the answer.
Does this mean that you overlook the significance of some information or miss things in the argument / passage?
c) Narrow down between two answers and choose the wrong one.
Note: you sometimes choose the right one, too, in this situation. You just don't notice afterwards because those ones are marked "correct" and naturally we all focus on the ones we got wrong. :)
From now on, whenever you narrow to 2 and then have to pick / guess without strong confidence, make a little symbol next to your scrap work for the problem - maybe a star or an asterisk. Afterwards, check all of them (first, just so you can prove to yourself that you actually do get it right sometimes). Next, ask yourself:
1) why was the wrong answer so tempting? why did it look like it might be right? (be as explicit as possible; also, now you know this is not a good reason to pick an answer)
2) why did the right answer seem wrong? what made it so tempting to cross off the right answer? why were those things actually okay; what was my error in thinking that they were wrong? (also, now you know that this is not a good reason to eliminate an answer)
Do this analysis *regardless* of whether you answered the question correctly. There's still something to learn even if you did get it right.
You mention using our SC Strategy Guide. What have you been using to learn how to do CR and RC? The only other things you mentioned were sources that have practice problems - but those don't give you the strategies or lessons for HOW to do CR and RC. They just have actual practice problems.
So you need to identify resources for CR and RC. We have a book for each one, of course, and there are other companies out there with their own books and lessons - but you need something that actually teaches you how to do these. :)
I think that's a good start for now - there's a lot for you to do here. If you do have further questions, let us know. Once you feel you've made significant progress on the major issues we've discussed (
at least 2-3 weeks), you can take another practice test to see whether you've improved in the targeted areas and, if so, to come up with a new list of things to tackle next!