BBA

The main topics that you need to focus on are verbal, quant, logical and general knowledge.
Quant also includes DI.
There's a book by Arihant but it's best if you get material from somewhere.
Ideally, you should join Pratham as it's the best institute when it comes to entrance preparation. (Bias towards Pratham as I was a a student there).
Make sure that you are up to date with class 12th maths as that's likely to be asked and it's a section of which most students are scared.
Gk is pretty basic but log on to clatgyaan and check out their yearly compendium.
Verbal is simple, logical reasoning needs a little practice though.
Finally, check out last year's papers on the website to get a fair idea of what your weak areas are and work on them.

Bachelor of Business Administration or BBA is a 3-year professional undergraduate course in Business Management, the minimum eligibility for which is class 12th from a recognized educational board with a minimum score of 50%. The course is divided into six semesters and comprises variants like BMS, BBM and BBS. It can also be pursued through Correspondence/ Distant learning modes and admission to the same is based on entrance tests carried out by different colleges and universities.
Some such entrance tests conducted by respective universities for admission into BBA course are:
IPU-CET
NMAT
SET
AIMA UGAT
Eligibility for BBA course
Interested aspirants for the course need to fulfil the below-mentioned eligibility criteria.
Completion of HSC (10+2 level) from a recognized educational board
English as one of the subjects at HSC
Minimum aggregate score of 50% to 60% at 10+2 level of education
Students who have appeared in HSC examination and are awaiting results are also eligible to apply.