Whenever you start an exam just remember that you can do  around 60% of total questions and you will be focusing on them first.

Firstly, there are some questions that is easy to do. You can do that then itself and move on.

Secondly, there are questions to which you can find answer, but it takes time to do calculations. Mark them for review if you can't answer then itself.

Thirdly, the questions to which we don't know answers. Or, questions to which "we can't seem to find answers." Get me ?

Yeah. If you know JEE syllabus, you already know the answers. To most of them. But sometimes it takes time to reach the answer. Read those questions completely.

Do the first questions then itself. Mark for review the second kind of questions(selected few). Read the third kind of questions. They'll stay in the back of your mind

Now as you finish reading all questions, do the second kind of questions. Remember to keep only a few into the second kind and do maximum number of questions then itself. While doing this, you'll again come across the third kind of questions. What surprises you now is how you now get some of the answers you didn't get before !!!

Our sub consciousness is an amazing thing. We still don't know the extend of its power. Have faith in it.

Study well. Cover your syllabus. Do mock tests confidently. Allen mock tests give an idea of the actual tests and most people don't have access to what you have. So you already are in the front of the race. Work hard. Be confident. Good luck !