Chad's Videos are the best. I was in the same boat and Chad's really helped. I ended up with a 20 on the gen chem portion, all thanks to chad. Once you master Chad, DAT Destroyer is excellent practice too.
This is my main strategy here. I watched all of chads for orgo (which is still fresh, because of orgo 2 this past spring) and gen chem. I feel solid on my orgo, but my gen chem needs work. I'm went back over his quizzes and am planning on 50 questions a day from each section in destroyer until the day before my test.