First you decide about subject which you find easy
Then you should attempt it first with speed and accuracy and after it second and next
Don't stick to one question and give to much time to it. Better you leave it and proceed further ,their are many question.
Try to attempt all questions which you find easy in first look in the whole paper
After that again go to starting point and see questions which can you solve by giving some time in whole paper
Now after doing all these thing and if you have time left then try to solve question by eliminating options
Don't do blind guessing. If you are 50% SURE then you may guess it
Solution to some of the problems/thoughts that can come during the exam:
You going to be nervous so try to understand that this problem is happening with everyone so don't try to think why i am getting nervous
Try to take deep and long breath for 2 to 3 minutes when you feel frustrated and nervous during your exam.
When you not able to solve few question then try to think that if you are not able to solve these question then others are also not able to solve these question (try to believe on your potential)
Try to keep aside your ego during exam (Sometimes there are few question which you think why am I not able to solve these question and end up spending lot of time on it. Instead leave that question and move ahead)
Few things you should do in between BREAK of two hours
Don't try to analyse first paper of JEE advanced and also try not to think about it
Try to escape away from other students and also not discuss anythings with them about papers its only create problems..
Try to find a park near your school and try to do lunch their and listen light music..