There are many self-help resources for those professionals who have failed the PMP certification exam on their first attempt and would still are aspiring to pass it on their second try. There is no dearth of such a crowd. There is actually no reason to panic because once you have given one exam and was not so fortunate, you can always go for the next two attempts. You have two more attempts to prove your mettle, and you have one complete year of eligibility period to retake the test. Having said that, if you do not attempt the exam or you failed in the remaining two attempts you sit for the test for the next year.

Another important fact to be noted is that if you don’t apply for the exam and your eligibility is expired you don't have to wait for another year you may apply for the exam.

SOME KEY FACTS:
The fee for the second and third attempt will be less than the first time test fee.
This criterion of members fee is different from PMI members and non-members.
The PMP Exam Fee for second and third attempts re-examination for their CBT is as follows:
For a PMI Member: 275 USD
For a Non-Member: 375 USD
And Fee for second or third-time re-examination for the paper-based test is as follows:
For a PMI Member: 150 USD
For a Non-Member: 300 USD

So where to begin, what you should do:
Not only in Exams but in life when you fail once, the foremost thing you must do is self-introspect (a self-audit). It is the first step towards improvement. You will notice the process group your performance was poor and you need to find the weak spots in those process groups and fill the knowledge gap where you lack.
In the PMP exam, you will have six kinds of questions, like:
Situation-based Questions
Formula-based questions
ITTO based questions
Definition based questions
Interpretational questions
Questions on Professional and Social Responsibility

OBSERVATION BY EXPERTS:

There are certain sections in which most of the participants face difficulty. Let us have a closer look at those sections:
It is observed that most professionals usually score low in ITTO based questions.
Participants often find these questions extremely difficult to solve.
In the list of tough questions, it is mathematical and situational.

SOLUTIONS FOR PHOBIA:

ITTO Questions:

Now, if you are too scared of the ITTO based questions, the best recommendation is to go through the PMBOK Guide.
Reading the PMBOK Guide will make you visualize the flow of processes in the Project.
Do not try to memorize the ITTO (besides being difficult, memorizing minimize the purpose). ITTO has the main purpose to not memorize them but to understand the flow.

Mathematical Questions:
These are another range of questions that many professionals find tough and skip studying, simply because they find no reason for wasting time preparing. They think that it can be compensated for other scoring areas.
However, it is an inaccurate way of preparation. Once you understand the concept, mathematical questions are pretty straightforward to answer and can be very scoring than other areas.
Tip: Try to practice the questions and understand the formulas used in the calculation.

Situational-based Questions:
The simple trick is that during this exam you have to think the way professionals think while doing their job. As you are attempting the PMP exam you have to think the way PMI thinks, assuming that you are working in an ideal world where everything supposed to be working as per the PMBOK Guide standard.

Strategy to Prepare for the Exam:
First of all, there is no need to panic. Keep your calm and take a gap for a few days, after which you may develop a clearer strategy and restart your preparation.

Recommendations:
The best way to prepare is to go for a recognized training program in which you are made to read PMP Exam reference books and try practice PMP Exam Simulators.
Take those test that contains all the questions (starting from situational to ITTO), so that you are not a victim of false confidence which might be a consequence of passing in practice test without ITTO questions.
The best tip is to read the PMBOK Guide as many times as you can.

Summing It Up:
There are many professionals who fail the exam and become nervous, frightened or simply lack the confidence or get demoralized. It is; however, not true, you may pass your exam in your next attempt.
PMP Certification is not like winning a race where only one participant will win. There are many who pass the exam and many who retake the exam and clear it. There is nothing to be frightened of. You just need to strategize, pursue exam preparation training, and plan wisely to correct the mistakes. So, go for it. All the best!