Some professors, especially but not only in Public Policy ask students to write policy briefs. If you are given an assignment like this, try this link.
The Policy Brief - OSI/IPF
Prepared by policy writing experts and former CAW staff Eoin Young and Lisa Quinn. Clear pdf handout.
Report Writing FAQ - University of New South Wales
A very well organised, readable site on university report writing.
Report writing - Academic Skills Programme - Canberra University
A detailed page with full guidelines. Information clearly laid out in lists and tables.