Ok, let me give you the most foolish things that one can do to not succeed in CAT.
1. Mark answers randomly. :x Believe me, i thought i would never do it. Imagine marking 10 questions blindly. Well I was so psyched out in hte last 5 minutes that something I had never done before, and knew was not be done, JUST DID IT.
2. Mark randomly with no pattern.

I just marked adcbcddcabbcdab.... with no pattern. A smart guy later pointed out that if I did mark randomly, I had a better chance if I marked all As, or all Bs, or Cs or Ds. He even proved it using some probability theory (which I still cannot prove).
3. Slow preparation in last week. I tought as I had done enough, i should slow my pace and learn to relax. Last 7 days just took 2 tests, and was very slow off the block in CAT. That was the end of CAT.
4. Start with Math

. Biggest mistake. It is not that my Math is week, but the CAT had really tough Math, and I thought I was screwing it up. Ended up screwing the rest of the paper too.
More blunders later, too many in a single mail really reflects bad on me.