Test preparation

Hi Himanshu,
You can start by taking a mock test and get yourself acclimatized with the test, you will also know topics you need to revise, your weakness and also your strengths. Prepare your study routine accordingly. 3-5 months is enough, if you devote yourself regularly and stick to your routine. Take as many mock tests you can after regular intervals and track your progress.
I hope this helps.

Career launcher is better since TIME is not up to to the mark, now. You can opt for IMS too.

You can opt for either Bull's Eye or TIME. Both the institutes are good for the preparation of CAT exam.

First, you should qualify GMAT and TOEFL exam. Score good marks in both the exams. Work experience is preferred by the universities. Try to get a scholarship. It is very expensive to pursue higher education in an American university.

You may register with any of the websites to get admission notifications. Many coaching centers also provide this service.
Please check the below mentioned link:
http://entrance-exam.net

Nothing is difficult, if you put your best and work hard. Different people have different opinion, you may take views but don't take decisions based on that. You may get in touch with the civil engineering students and start your preparation according to that.

You should focus on NCERT and join any coaching center.