Hi,
I am a international student who plans on retaking GMAT.
I've already taken GMAT twice; first attempt : M46 V34 650 second attempt : M47 V34 650
As you can, my score didn't improve at all.
The result of the second test was really frustratung because I studied for three months after I took the first test.
Then, I realized that how long I study dosen't improve my score; how I study matters.
So I decided to renew my study plan.

First of all, I will explain how I've studied.

First, I solved OG 12th & OG Verbal review and then took the first test.

Some people say that even though I solved OG, I should review it at least twice, but I thought that that method was inefficient because whenever I saw questions, automatically, answers came to my mind.

So I started to study with paper based GMAT questions and some materials called GWD.
Both are retired real GMAT questions. I thought that the best way to sduty is to keep solving problems, so I did so.
But the problem was that both materials did not have official explantions and that sometimes they have incorrect answers, so I had to depend on unofficial explanation on the Internet. As a result, I couldn't analyzed the problems thoroughtly. However, I believed that solving hundreds of questions would help me understand although I didn't analyze the quesions thoroghtly, so I kept doing so.
Looking back, that was the main reason that I failed to improve my score, which made me renew my study plan.

Thses are questions while I was renewing my study plan.

1. Is the math review in the OG good enough for preparing GMAT math?

2. Is there any books that contain only questions?
(I found "1037 practice questions for the new GMAt" in Amazon. How is it?)

3. Is it worth buying online tests such as Manhatten CAT?
( I tried free Manhatten CAT, but I felt like it was quite different real GMAT, especially Math and RC)
What about others such as Kaplan?

4. I will buy Manhatten SC 5th edition, should I buy the OG 13th to study Manhatten SC 5th edition?