In addition to the sites listed under “Writing” in my Links, here are a few good sites I have found recently.
Rhetorical functions in academic writing. You will find:
Describing objects, location, structure and direction
Reporting and narrating
Describing processes, developments and operations
Classifying / categorising
Including tables and charts
Comparing and contrasting: similarities and differences
Expressing degrees of certainty
Expressing reasons and explanations / cause and effect
Arguing and discussing
Writing research methods
Writing research results
Writing research discussions
Writing research abstracts
Each one is illustrated with real examples. Very good for upper secondary and tertiary students.
Here is a university level Example Academic Essay illustrating through highlighting in-text citations, referencing, quotations, summaries and paraphrasing. The site it comes from is English for Academic Purposes, practically a whole online course in academic writing. (English Language Centre of the Hong Kong Polytechnic University.)
Writing for Academic Purposes is a comprehensive online text (in frames) from Using English for Academic Purposes: A Guide for Students in Higher Education by Andy Gillett, School of Combined Studies, University of Hertfordshire, Hatfield, UK. The parent site also addresses other aspects of EAP. Very good. Includes exercises.