Duncan is taking notes on Karin Slaughter’s interview about writing.

I think, really, what makes thrillers work is that they have to have a beginning, a middle and an end. When you – writing crime fiction, when you want a really good story, when you want a compelling read, you have to focus equally on plot and character. And you have to make sure that the reader cares enough about these characters so that when bad things happen, they want to read along.

And being a Southern author, you know, I grew up with Flannery O'Connor, and I love reading her essays because she was such a—not just a wonderful writer, but she was wonderful at talking about writing.

Which will be most helpful as Duncan re-reads his notes to find the central idea of the interview?

Beginning, middle, end
Plot & character - important
O’Connor- Southern author
Slaughter loves essays

Duncan's notes on his interview to author Karin Slaughter show the different topics the author talked about during the interview regarding the main topic of writing. The notes that show how Slaughter reveals that in order to have a good story the author needs to focus equally on plot and on characters is probably the main point of the interview and should be the central idea of it when Duncan is writing it. Although Slaughter talks about other important topics when writing, they all work as secondary information when compared to the plot and character remark.