Before you start preparation, make sure you know the pattern of the exams you are planning to take, in detail. You can be sure of one thing that the tests will check your fundamental knowledge itself. If you have prepared well for your 10+2 board exam, half your preparation would be done.
Bba entrance exams generally covers following areas to study on:

• Quantitative aptitude
• General awareness
• Reasoning
• English

Topics under qunatitative aptitude are:

• Arithmetic
• Geometry
• Algebra
• Mensuration
• Number System
• Series
• Commercial math
• Data Interpretation
• Data Sufficiency
• Topics covered under English are:
• Reading comprehension
• Vocabulary
• Grammar

REASONING covers the following topics:

• Logical and Mathematical Reasoning
• Deductive Logic
• Statement Assumption
• Analogy
• Visual Reasoning
• Series
• Data Interpretation

Books you can go for:

• Self study giude BBA(arihant)
• BBA soleved papers for Entrance Exam(Career Launcher)
• Arihant's GGSIPU BBA Cet 2018(if you have applied for GGSIPU)

Hope this helps
Thankyou for contacting Careers 360