Neeraj:
The answer will depend on your own personal learning style. However, for the incorrectly answered questions it is most important to understand why you missed the answer, not just what the right answer is.
My experience is that the exam simulator is spot on for the kind of wording you will find on the actual PMI exam. The exam's purpose is to test your understanding of the material, not your necessarily your knowledge of it. There are a lot of "situational" questions on the exam that do this as the wrong answers (called "plausible detractors" in the testing world) are often correct answers for other processes or for a similar, but slightly different situation. So, from that perspective, it is vital that you thoroughly read the questions and understand what it is asking for.
Good luck,
Harry