How hard is the PSAT and what should i heavily study to prepare?

Next month i will be taking the PSAT. Now, i am a 4.0 GPA student, enlisted in multiple extra curricular's, and getting into to the Top 50,000 would just be astronomical for me. I have been studying the materials provided to me by my school, but what is there for me to go beyond what is presented in the practice test and study material in the packet provided by the NMSC?