There's a book out there, called "Pushing Electrons" which is a must if you want to understand the nitty gritty stuff about Orgo. i absolutely loved Orgo, and didn't fall upon that book until the final day of my last quarter of Orgo. I did well in the class nevertheless, it was very enjoyable. But if you can get your hands on that little book, get it. It's been a life saver for many of my friends.
Also, another orgo (very interactive) book I liked was Solomon's. It's a big thick purple book and this guy wrote it. Check out the book store to see if they have deals on it. Overall, you don't need any extra books to do well in Orgo. these are just additional resources you can use in case your school text does not address something well enough.
Cheers!
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