Dear Monisha ,

If we go through MCA  common entrance test so it is basically mathematics,computer awareness,logical reasoning ,English, general awareness but it will change rapidly as per which entrance exam you will conducted but mostly all of same so dont worry focus on verbal ,reasoning and aptitude because it is most priority and important things in every entrance test .

For MBA like CAT,XAT,NMAT,IIFT and much more highly demanded entrance exam test  time management is most important is you wants to good score in entrance test then first of all go through previous years question papers where you know about the pattern and types of question are arrived.Then practice on it from like lots of sources are available or you can take help of internet and every week you can attended mock test for better visualization where you stand or in which topics you facing problems.In this way you will understand your strength and weakness and  mostly focus on this topics where you score less if you start solving problem from easier to harder level then you  will get confident to achieve your goal.

i hope it will helpful for you and best of luck for your exam

Thanks