Brandy and I have been talking about putting call-out boxes in each chapter of College Writing that list "common pitfalls" in student writing. For example, in discussing how to formulate a workable thesis, we might list such common problems as:
- too broad
- not feasible
- matter of individual opinion
- moral argument
- explanatory rather than argumentative (x is important; people need to know about x)
Or in discussing outlining, we might list common problems with claims:
- claim too broad
- claim irrelevant to thesis
- claims too similar to each other
- claims not in full sentences
What are some common pitfalls in students run into when writing 1120 papers that you think are worth warning them about?

My students just turned in the classification paper, which includes the first draft of one the paragraphs for the research paper. I'm seeing many students taking single pieces of information from their sources, pulling the information out of context and leaving out other good evidence.
"No real counter-argument," or "no academic counter-argument." That's gotta be one of the top three common pitfalls for both thesis statements and claims.
Mike's onto something important. There are a ton of varieties of this (Gerald Graff gives us some ways to talk about it, so does Ralph Johnson), and some sidebars addressing it would be awesome.