1. Multiple Assignment rather than Multiple Pathways
This is a common mistake, since differentiation is often presented to teachers as multiple assignments or projects going on at once. To be perfectly honest, it is easier to explain to teachers that they can find and copy multiple "worksheets" on the same topic rather than create multiple paths for learning.
2. Differentiating by learning style vs. learning needs
We can classify students into learning styles and prescribe learning activities for them without much gray area. Learning needs is more vague and uncomfortable for teachers since these learning needs change constantly.
3.Differentiating by achievement level rather than by students' current learning level.
Here again students learning levels change constantly based on the content, the interest and background knowledge. This requires continuous assessment and adjustment to grouping and instruction.
4. Differentiating up rather than down.
I really think this should say "down rather than up". We tend to differentiate by "dumbing down" instead of starting at the standard and looking up. If students have trouble getting to the standard we need to look for ways to support them to reach that standard.
I read this recently and thought it was a great way to think about the teacher's role in a differentiated classroom.
“Teachers in Differentiated Classrooms are students of their students” Author Unknown