You should have started studying at least 3 weeks ago. Whatever. Just do all the problems on the study guide, and review what you get wrong(this is where you make your money, understand what and why you got wrong answers).

I think reason why people do so poorly is because of the time constraints, and the format in which the questions are asked. Besides that, the exam is pretty straight forward, nothing out of the ordinary. I took it 4 years ago, I think. But I went through the study guide twice and that was enough to get me one of the highest grades in class. Just practice until you can't get it wrong anymore, then you'll be confident thought to be like that was easy.