Hello Aspirant

Here are a few things which you should keep in mind while doing choice filling in any counseling:

1. Check the last year opening and closing ranks of the respective counseling. From there you will get an idea about  which seat you will be allotted.
2. Understand that how the counseling authority allot the seats. For example if you have filled 50 choices and you have locked them. Now sometimes they check your first choice and if you are getting that seat they will allot you otherwise they will check your next preference or choice. In this manner they check your all the choices one by one.
3. Never try to skip for the seat which you know you can't get but is your most ambitious choice, if you can't get that seat it will be skipped.
4. Always fill the choice in the order of you preference. Never fill an less preferred choice above and more preferred choice below.

Hope this helps