Start with biology. Finish biology in first 45 minutes, all 90 questions. This includes both solving and marking answers in the OMR sheet.
You can extend this time to 50 minutes maximum.
Then you should move to chemistry. Try to finish it in 50 to 55 minutes. Move forward of you can’t solve a question and mark it for later. Fill the OMR sheet in this time also.
Then move to physics, it takes around 1 hour for Physics. Again, move forward of you don’t get an answer, mark it for end. Fill OMR simultaneously.
Now, you are left with approximately 15 to 20 minutes. In these last minutes, you should look for questions that you have marked for later. Again go in the same order that is biology, chemistry and physics. Try to solve questions which you couldn’t solve earlier by different methods, you may get some right answers in the end.
This method was used by me on my NEET exam. This is the most effective method. Also this method was suggested by our teachers from coaching class.