How do I prepare for the NICMAR entrance exam if I'm planning to get a top 5 percentage scholarship?

In the NICMAR admission process, maximum weightage is carried by NCAT Exam (150 Marks). It has three sections which are as follows:

Preparation Time: 3 Months 

• Quant: R.S Aggarwal or equivalent aptitude books will be best for this section. Some questions are really easy that can be solved in less than a minute. If you want to maximize your score, practice moderate-level questions of other MBA entrance exams. Be thorough with percentages, allegations and mixtures, ratios, time speed, and distance, and like topics as questions are asked from these topics. 
• Data Interpretations: There are multiple books available for Bank PO Exams in which such sets are available. You can just go through them. It is sort of a puzzle so you will have fun doing it.
• Verbal and GK: Reading Comprehension is very easy. Just practice a few comprehension available in any competitive exam book. This section also tests your vocabulary as synonyms and antonyms questions will be based on your vocabulary. GK questions are really easy and you’d have read them somewhere even if you are not a news freak. To sum up, if you read the newspaper daily and practice a few comprehensions, synonym antonym, grammar questions, you are more than ready for this section.

In NCAT, speed matters the most. You should solve the easy questions first. Do not waste your time if you are finding any questions tough. Just move on. Most importantly, you should improve your grade in UG. Participate in competitions and earn certification. Nothing much can be done as what you have done earlier matters here.

During the personal interview, brush up on your basics of civil engineering (concrete and building material especially). The basic HR questions will be asked like why do you want to join NICMAR, what are your long-term goals etc. They also test your speaking skills by giving you a topic to speak on. So, you can also practice it as it will be good for you in the longer run.