1. After observing the syllabus
2. After seeing the previous year question paper(s).
3. By assuming that no one single book is enough to learn a subject well and deep.
4. From my experience in these subjects I had studied for my BCA/MCA/M.Phil and UGC-SLET examinations
Please go through the list, read the remarks and facts I have shared. Decide depending upon your thirst for studying those subjects and more importantly to your budget.
As AMIE questions are mostly based on critical thinking in nature (You cannot vomit by memorising all the facts about a subject into examinations. You need to study, learn, digest and apply them in your answers), I have prepared this exhaustive list.
(Please don't curse me for the huge list of books I have mentioned. Better choose them on observing the contents, comparing with the syllabus from a book shop, and more importantly follow your intuition before buying!)
All the very best
Books Recommendation for Computer Science and Engineering