There are a lot of beginner mistakes to starting an Obsidian Zettelkasten in college.
Out of all of them, however, these are the three biggest traps:
Not connecting notes between classes and semesters together
Not connecting your class notes to your own learnings
Not creating MOCs out of your class notes
1. Not Connecting Notes Between Classes And Semesters Together
When first creating a Zettelkasten, it can be easy for students to fall back into the sequential notetaking style they are so used to from more traditional notetaking methods.
But the power of a Zettelkasten comes in the connection between seemingly unrelated ideas. For example, connecting a note from Introductory Biology about recessive genes to your History note on the massive chins of the Old English Aristocracy caused by incest. You have to make sure that you connect notes between classes and semesters together.
To remind myself of this, I reflect on this quote regularly:
"There are no rigid disciplines in the universe, only concepts."
All disciplines--Biology, Neuroanatomy, Behavioral Statistics, American History, etc.--are just highly related concepts linked together into a coherent and more easily digestible form. It's through the linking of these highly related concepts, from class to class from semester to semester, that your knowledge base starts to grow. Your Zettelkasten becomes more than the sum of its individual parts.
Your knowledge compounds over time.
2. Not Connecting Your Class Notes To Your Own Learnings
Many beginner Zettelkastener's--it's a word now I made it up--think their learnings inside class are separate from their learnings outside class.
As a result, they separate off their class notes in Obsidian from their notes on Podcasts, books, blog posts, and more. But as said earlier, the power in a Zettelkasten comes from connecting ideas together and scaling them over time. Your personal learnings can only help in this process.
In fact, it will likely only make you more interested in your learnings inside of class. Double Whammy!
3. Not Creating MOCs Out Of Your Class Notes
As your Zettelkasten grows throughout the semester your class notes will soon start to become overwhelming.
Some notes are connected to other notes but there is no clear map for the class. The mistake is to leave them floating in the depths of the nether realm. This will only guarantee you never touch them again and don't form an accurate mental model of the class.
The solution is to create Maps of Content (MOCs) out of your class notes.
MOCs are notes that serve as a map for a interconnected web of related notes. Your class MOCs serve as hubpages for the highest order notes you take for your classes. They serve as a navigational hub and also can build deeper understanding with the class material.
There are many many more beginner mistakes to starting a Obsidian Zettelkasten in College. But avoid these ones, and you will stay away from the worst of the traps.