Hello everyone. I wanted to briefly share my GMAT experience as I think there's some things that might help you.
First, I wish I had known about GMATClub sooner. I only found it a few weeks before the test. At any rate, I studied for the GMAT on and off for about 3 months. The last three weeks were almost exclusively studying each night and all weekend. I used the Manhattan Guides and found them excellent.
I think the two keys to success are:
1) Manage time appropriately. I tried to get it to where I could answer 75% of the questions in about 1:30. This gave more time for the harder questions. If you know you're not going to get the answer, then just guess intelligently and move on.
2) Work OG problems over and over. Once you've gotten a problem right, do it again. Then, do it again. After a while it will feel lame because you know the answer already. However, this is really what caused my to turn a page. It forced me to learn the various problem types. The real GMAT didn't veer too far from these basic problem types, they were just presented slightly differently.
My CAT scores were as follows (I don't have dates or the Q/V splits):
GMATPrep #1: 700
Manhattan #1: 670
Manhattan #2: 720Knewton
Manhattan #3: 680
Manhattan #4: 700
Manhattan #5: 720
Manhattan #6: 730
GMAT Prep #2: 740
Actual GMAT: 760
I don't have a great story for the actual exam except two points:
1) I got the first quant question wrong. The problem came up and I went completely blank. I worked it three different ways and noticed that 2 minutes had passed. I took another approach and still was getting no where, so I just selected the answer closest to what I was getting. After the test I remembered the problem and worked it out on my own. Turns out it was very easy and I had gotten it wrong. I guess the key learning is DON'T GIVE UP! Just move on and forget about the past. Also, hopefully this settles some concerns that the first 10 questions are very important.
2) I didn't get any of the traditionally very difficult quant questions. No combinatorics and no crazy rate problems. My probability problem was a relatively easy DS question. There were several overlapping sets problems but Manhattan's process for solving these makes them extremely easy. Learn that process! Clearly there's some luck involved.