Short answer: Choose one resource per section, practise daily and take regular mock tests. CAT rewards consistent practice over book collecting.
Quantitative ability
Refresh basics from school maths first, then practise topic-wise sets from one book.
Verbal ability and reading
Read widely and practise reading comprehension daily. A single verbal practice book is enough alongside reading.
DILR
This section improves through solving full sets under time. Use a practice book and review how you chose which sets to attempt.
Mocks
Mocks are usually online, so books are only part of the plan. Use them for topic practice and review notes.
Frequently asked questions
How many CAT books do I need?
One practice resource per section plus mocks is a workable starting point.
Are old CAT books useful?
Concept sections are, but check that the book matches the current pattern.