Chug through as many Rosh as possible. Between the diagrams and the explanations, it's all you need assuming you do most of the Qbank. If you're consistently bombing one topic, consider reading the associated chapters in Tintinalli/Rosen. Also, the Rosh score predictions are shockingly accurate. Of the actual scores I remember (including my actual written boards), they were always within three points of the Rosh prediction.