A PLAGIARISM SCANDAL AT BROWN. The two best ways to avoid accidental plagiarism are to only work from hard copy, so that every word in your manuscript is put there by you, avoiding the risk of accidentally cut-and-pasting others’ words in, and to never let research assistants do any actual writing on your project, but restricting them purely to research. That won’t keep you from using, say, a phrase that comes to you as if it’s your own but is really something you read elsewhere, but most plagiarism cases aren’t about isolated phrases or sentences.
My general thoughts on plagiarism — including a defense of Joe Biden — can be found here, in a chapter from the book I wrote with Peter W. Morgan, The Appearance of Impropriety: How The Ethics Wars Have Undermined American Government, Business, and Society.