There should be a proposition, a thesis, that you re trying to demonstrate. If they can identify the thesis and state it they are on their way. If they are writing a fifteen or twenty page paper they should be able to say what they are doing in one sentence. If they can t the paper is usually a mishmash that wanders about. The concept of analysis is even more difficult to convey to students.
Students are very different in their ability to do analysis.
A lot of them seem to have been taught in high school that everything you say has to be documented. Which was important in high school, because it forced them to ground their assertions in something. But it makes them frightened to have their own idea or think their own thoughts. I have had students turn in four page papers with three and a half pages worth of quotes. I tell them I don t want to see any quotes I am interested in what you think.