I have been studying for PMP for two months now. I am using Rita's PMP exam prep and Andy Crowe's How to Pass on your First Try as well as the PMBOK as supplementary material. I have moderate project management skills. However, with some of the exams I have been taking online such as Oliver Hamm's 75 Questions i still cannot seem to score above a 55%.

May someone help me in knowing where I am going wrong?