You have the right books for verbal, so put in as much effort as possible for those two books - especially Manhattan SC. In fact, I advise you to read Manhattan SC at least twice.
It's also important to fully review every OG verbal question - even the ones that you answer correctly. This reinforces the material, helps you to get into the GMAT's logic, and builds confidence. Also keep an
error log, which is crucial for improved performance.
But I'm still not satisfied with my response. What else can you tell us about your studies? What do you find difficult? Are the Powerscore CR Bible and Manhattan SC guidebooks easy to understand, or do you struggle at times?