I have tried previously to impart unto the junior graduate students in my research group the value of managing their reference material (articles, proceedings, digital books, web pages, etc) using some form of software tool. They have seen such tools as unneeded and extra work, and have failed to see their value until it is too late to effectively start using them.
At my next opportunity to motivate students to use such a tool, I want to try a different tact: Motivation by Challenge. I will admit, such motivation I believe will only work if I have the authority to make them do it, but I think this is a typical situation for assignments.
I would present the students with a collection of papers, 10-20, depending upon how much pain I want them to experience, and instruct them to format references for a journal. Then, after they complete that work, “change my mind” on which journal to use, and get them to do it again. This will expose them to the fiddily nuances of reference formatting of different journals. I can them expose them to a reference tool (Mendeley, Zotero, EndNote, JabRef etc), and show the how quickly they can solve the two prior assignements, as well as store their files, search the full text and store their annotations. Hopefully, this will motivate them to invest the time to learn a tool, and use it in their daily work.