The Quora page
answering this same question offers wonderful answers to this question. In many ways, this article is going to be a rehash of the bunch of things already mentioned there (and the Quora page is much better at answering that question)
The suggestions/posts fall broadly under three categories
Randomness plays a huge role in the CAT score.
This is probably the most infuriating. Quite a few guys who scored 99.5 percentile will tell you that they thought they had done the previous year also decently well and scored only 94th percentile. Throw in different sessions, the way the IIMs treat incorrect answers, normalization, there are quite a few random variables into the mix. So, do not over-analyze the score.
Till last year (particularly last year, CAT 2013) the scores gave us the feeling that they punished inaccuracy harshly. In CAT 2014, they appear to have reversed the trend and gone in with a plain vanilla +3/-1 and encouraged calculated chance-taking. God knows what they have in mind for next year.
It is not such a big deal
Most successful business in our Country (in fact worldwide) were started and run by non MBAs. The CAT is something that you will most likely forget about in 2-3 years time (whether you crack it or not). The score is not a reflection of how capable you are or how well you can do in life. As one of the posters in the forum said "I'm not familiar with that particular exam, but IMHO the ONLY thing that such standardized tests measure is how well you take tests.
CAT tests pretty much how well you can take CAT, and then we take this as a proxy for something else. You might be better at getting to that something else without having the ability to crack CAT. Go for it. God knows our Country needs more entrepreneurs.
Have another go, make some changes
Be less vulnerable to luck, cover all bases. Read a lot; prepare from basics. Do an enormous amount of drill. Catch a break and launch yourself into the preparation
What I would add
Be less vested in the result, and enjoy the preparation process more, I know this is tough to pull off; but the guys who crack this exam are the ones who take up the preparation process as a joyful exercise rather than a fearful one.