You have not revealed about academic level for which you need suggestion. For all the professional degrees whether it would be CA, CS, ICWA or any other degrees, conceptually you should be very clear to get exemption in the said subject. You need to practice more and get all the logical queries solved on your self. Don't go for specific type of sums being asked in examination but chose specific verities and understand it by all means and imagine types of questions which may be asked and get the solution of simulated examples.
Here we are supposed to be the expert in the given subject.