Test preparation

I say Telugu is very widely chosen. English is difficult, because preparation for it will be difficult, in view of the range of the subject.

FACE 2 FACE MAT by BS SIJWALI and AJAY SINGH

In India it is a two way process
Firstly grasp the concept ,read as much as you can .revise for 24 hours.a week(you thought a day ) .do previous years paper , remember important points on your tips .
But the main point I've experienced be cool minded on the d-day . And don't,dont ever go with hungry stomach because the invigilator will eat Samosa in front of you.
Second
If you have a quota certificate don't give a shit to good marks you are already selected.
As said by baba banchoddas chattriwala
Ache marks k lie Kabil banu ,nahi ban sakte tu quota wale banu

Just clear your basics first, then solve as many as questions as you can. Start from the simple ones and then increase your level accordingly as it will give you confidence. Solve atleast hundred questions a day from a good book for JEE Mains

You need to be a graduate with 50% aggregate marks for all years.
You can even give CAT if awaiting 3rd/4th year degree result

There are numerous options after B. Com
Two most popular options are - MBA (or some other post-graduate degree like M. Com) and Job.
If your family's financial condition is stable, you can go for MBA. To get into a good MBA college you will need to work very hard.
Second option is starting a job. Post your resume on online portals like Naukri, Monster etc and start looking for a job.

If u are serious to become an ias officer then you should take ba because it will help more in your upsc exam

You should start your preparation for CAT in third year.