`1.` It is that you're not taking good enough notes.

`-` Dẫn chứng: One of the reasons you may have identified for underperforming is that you're not taking good enough notes.

`2.` Hurriedly scrawled notes from class can be difficult to make sense of when I come to revise from them, or even to write an essay based on them.

`-` Dẫn chứng: Hurriedly scrawled notes from class can be difficult to make sense of when you come to revise from them, or even to write an essay based on them. 

`3.` You may fail to get a strong enough grasp of the topic.

`-` Dẫn chứng: It's all too easy to misunderstand your own notes and fail to get a strong enough grasp of the topic. 

`4.` Because good notes are readable, useful, and logically organized.

`-` Dẫn chứng: It's imperative, therefore, that you produce good notes from each of your classes and from the book you use - notes that you can read, that are useful, and that are logically organized.

`5.` You should try to type them up at the end of the day, while they're still fresh in my mind.

`-` Dẫn chứng: If you make notes by hand - in class, for example - try to type them up at the end of the day, while they're still fresh in your mind.