By doing it right! By learning from the basics and retaining a sense of wonder about math.
I will elaborate on this after a short story -
According to legend, Archimedes was killed by a Roman soldier after the capture of the city of Syracuse. He was contemplating a mathematical diagram in the sand and enraged the soldier by refusing to go to meet the Roman general until he had finished working on the problem. His last words are supposed to have been “Do not disturb my circles!”
The story is perhaps apocryphal, but conveys the point beautifully. If learnt well, math is endlessly fascinating.
Try the following question (This is an old famous puzzle). Fill the cells given below with natural numbers from 1 to 8 such that no two adjacent cells have consecutive numbers. Note that two cells are considered adjacent if they have even one point in common.
Now, say you are learning the topic on Averages. Think about this, a teacher says every student in the class should score above-average. What is wrong with that statement?
Let your mind rest on numbers and number patterns a little bit. Guys who love numbers love the numbers 243, 343, 729, 1729, 73 etc. For different reasons. See what draws them to these numbers. Think of Quant as a wonderful way to exercise the grey cells, fret less about marks and percentiles.
Not for nothing is Mathematics considered the queen of the Sciences. It provides a fabulous brain-exercise tool kit and is endlessly fascinating.
If none of these works, power through. At least as a subject it deals more in absolutes than anything else. You may never be able to see what is funny about PG Wodehouse, or the beauty in a Monet. But math is quite unlike literature or Art. Any which way you look at it 3 + 2 = 5.
This is also probably the reason why math teachers are the ones who are very confident of their trade.
Take me for example, I am a math teacher and on critical issues I have no discomfort with absolutes. There is little room for "it depends" on key points. In case you want to know what is the best avenue to prepare for CAT, or who offers the best online coaching for CAT. The answer to this question is not ambiguous, it does not depend on anything, there are no grey areas.
There is 2IIM and then daylight before anyone else. :-)
Jokes apart, prepare with a sense of joy. Math is most definitely not this thing that you need to have a phobia about. Anyone afraid of math is someone who has not been taught math well. Learn from basics, learn with joy - the fear will go away.
Best wishes for CAT Preparation.