Writing is judged on 

1. Clarity
2. Novelty
3. Contribution

You will be judged more heavily on 1. than your work.  We almost never
teach 1.  This course is about 1.

There are a few principles.

1. Put the important stuff where a reader in a hurry will see
   it. [EVERY reader is in a hurry!]
2. Don't make the reader work harder than necessary to understand it.
3. Unlike other forms and purposes of writing, make the writing
   'disappear' in the readers' eyes, so that only the ideas remain.