Anuj,
There is a difference between intelligence and being able to give a good exam. You are not using your intelligence in the right way. Give real effort first in understanding your cause for failure. It is either lack of enough hours, or practice, or concepts. Doing a sum correctly isnt all important, doing it in time is. I've watched and watched in shock as all my friends passed while I flunked over and over again. This may is my 5th attempt. Am going to pass one if not both.
My problem was 'HOURS'. FIND YOURS.