Critical reading help needed

On the December SAT I got an 800 on math and writing but a 680 on reading. I am taking it in January and I am wondering what I can do to increase my reading score. If anyone has any suggestions please tell me, thanks.

Study vocabulary. Practice Sentence Completion on the Official Guide, and Erica Meltzer’s book, and memorize the vocab there. Practice with Official Guide SAT book, take all 10 tests, and check the answers on the College Board website Studyguide section.