I want to become a National Merit Scholar Finalist! HELP!?

I'm an upcoming junior and I am planning on taking the PSAT this October. I took a practice test 2 weeks ago (actually it was the official 2009 Form S test from a friend who graduated) and I received a total score of 194 (M:68, CR:64, and W:62). I really want to become a National Merit Scholar Finalist, and the score i need is a 212 because i live in Ohio. I have planned to study the entire summer but I am getting both anxious/overwhelmed. Could anyone get me tips or tell me what they did to study for these tests? I bought 3 books, the Princeton Review 2011, Barrons 15th ed., and Kaplan 2012 all specifically for the PSAT. I'm freaking out and I really need to get my score higher, can someone help!?