I am preparing for Object Oriented Design interview for weeks. But, during the preparation I got lost many times. I don't know what to study or what resource (ie. book, webisite, online-course and etc) to use. I read/watched several tutorials on blogs/youtube. But, the authors are experienced guys who knows OO Design very well. And, also there are tons of blogs and books related to OO principles. I read some books but they explain basic concepts, and don't go for bigger/real-project examples.
I have question for guys who were successful on OO Design interviews. Can you share with us your success story? How did you learn OO Design techniques? What resources (book, website, course,..) did you use for preparation?

Thank you in advance.