PSAT Questions, Please Read?

I am taking the PSAT in two weeks. I have been studying for a while and I am consistently getting 80 or close to it on the math, around 75 on the reading and high 60s to low 70s on the writing. I want to get as close to a 240 as possible and to qualify as a national merit scholarship finalist. What books do you recommend for the math, reading, and writing sections? Any other tips?