Get Kaplan 2400 and work through the reading section (oh, hell, go through the whole book). I got a lousy 680 without studying and I have to say that after studying that book for a few days, I'm already in the low 700s.
Oh, and memorize a word list a day. As Barron's 2400 says: "A word list a day keeps the average score away!" Speaking of Barron's 2400, after Kaplan, get it and work through that.
Have you used up the blue book tests yet? If not, save one for after you've read all of Kaplan 2400, and another for after you work through Barron's 2400.