For verbal in general (not just CR), try articulating:
- why was the wrong answer so tempting? why did it look like it might be right? (be as explicit as possible)
- why was it actually wrong? what specific words indicate that it is wrong and how did I overlook those clues the first time?
- 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?
- why was it actually right?
You can do this even when you get the right answer - just pick the wrong answer you think would be the most tempting. This can really help you to understand the thing that's making you fall down right now on CR: how to distinguish between that really tempting wrong answer and the right one.
(Oh, a side note re: narrowing down to 2 and picking the wrong one. You may have picked the right one sometimes when doing this, but not noticed because you concentrated on the ones you got wrong when reviewing. It's important to review everything you got right as well - make sure you got things right for the right reasons. Also, you may think of some easier / more efficient way of doing a problem after you've already done it and gotten it right!)
Re: quant, spend at least some of your time making SURE that you won't lose points on sub-700-level problems. You can get all 700+ problems wrong and still hit your 670/680 goal. If you get enough sub-670 problems wrong, though, then you won't hit your goal. In particular, watch out for instances of careless mistakes - where you know what to do but get it wrong anyway. When you spot a careless mistake, ask yourself WHY you made that mistake and what habits you could either implement or break in order to minimize the chances of repeating that careless mistake.
In general, the questions get harder as the numbers get higher in OG - so focus more on the mid-to-high numbers. You can also try GMAT Focus (
www.gmatfocus.com) but be forewarned that this is adaptive - you actually have to lift yourself to the higher levels by getting lower-level questions right first. This more closely simulates the real test experience, though, so it's better than doing only hard ones.
I still wouldn't take a practice test more than once a week. I'd take one 2 weeks before the real thing and the last one 1 week before the real thing, at the same time of day as the real test, and under full, official test conditions.