SAT Score falling

Hi,

Before summer started, i took the March SAT and got a 2150 (740 Math, 720 Writing, 10 essay, 690 Reading). My goal is 2300+ on the upcoming October 2015 SAT. In June, I used the blue book by CB and i kept getting high 2200’s on my SAT. However, recently, my scores have been going down and I’ve only been averaging 650 on each section. I am also running out of tests from the blue book so i have a couple questions:

  1. What are some tactics I should look into to help me improve my score??? I don’t know why but I am missing like 5+ questions on each section and I don’t know why? My goal is for 800 Math, 750+ writing and 750+ reading.

  2. Which prep book will help me better improve my score??? Mainly, in math, i make careless mistakes regarding addition or I miss questions about surface area/volume of 3D objects. My main problem is CR passages and analyzing author’s tone and meaning of the passage.

  3. Are there any other tips you guys suggest for helping me break the 2300 barrier?

Thanks,

SD