Hello Sandeep, 1500 rank in OBC category is a very good rank. You will get Best courses like CSE, ECE and Mechanical branch in most of the NITs. For example, you can get CSE in NIT Jaipur(last year opening rank was 1187 and the closing rank was 1892 for OBC Category), you cant get CSE in NIT Bhopal too( Last year Opening rank: 1275, closing rank: 1890). I suggest you register for JOSAA counseling. I am pretty sure you will get the course of your choice in the best NITs. I am providing the official link of JOSAA 2018 cutoff. it will help you in finalizing your colleges and branch. NITs list is from page no. 51 so start looking from page 51 in the cutoff list.

JOSAA 2018 cutoff: https://josaa.nic.in/webinfocms/Handler/FileHandler.ashx?i=File&ii=139&iii=Y

With this rank you can get top branches like cse and ece at top NITs. You can even get seat in NIT Warangal which is the best NIT of the country. You can check cutoff of all the courses in NITs bu going through the link given below.

https://engineering.careers360.com/articles/nits-cutoff-for-top-btech-branches

Hope it helps.

All the best.