Exam

No, you may not get admission in NITs with this score if you belong to the reserve category. You can try for Thapar University, AMU, etc.

While doing your UG you can start preparing for CAT & other exams. You can solve aptitude questions, prepare for vocabulary, read more and more newspapers, improve your communication skills & interview skills, learn how to appear in gd.
Make time table and divide the preparation for each section of p

Hello Deepankar,
Yes, you can get Government college of UPSEE as your rank is good. Please check the college detail in the link provided:
https://www.shiksha.com/b-tech/resources/upsee-college-predictor

Hello Muhammad,
You need to get at least 75% in board exams (12th). So, if you have only scored 72.2% then even if you clear JEE Mains and Advanced, you cannot get admission.

Hello,
Please refer this to get more insights of the colleges based on your rank.
https://www.resonance.ac.in/reso/news/jee-advanced-branch-allotment.aspx

There are NITs, colleges under DU and many good ones which will give you admission.

No way, you need to qualify JEE advance with a very good rank to be eligible.

You probably will get MANIT if there isn't a top 20 percentile criteria. Make sure that you fill the JoSAA entries and have some alternative as a backup too.