Overview
Oftentimes, the most efficient way to learn more about advanced writing (and researching) in a discipline is to look at good models. These models can be from publications (i.e., reading what's already out there). However, it's sometimes even more useful to read the writing of other graduate-level students.
Annotated Sample Student Papers
The two images below show professional business letters. The annotations--provided by Heidi Livingston-Eisips, a faculty member in the College of Business--direct your attention to aspects of the paper that you should notice (i.e., what the author did well).