This is a great overview of an Illustrative essay, with links for introductory paragraphs, body and conclusion.
English Works Writing Index
Wonderful site with exercises for prewriting, essay structure, lots of information about a wide variety of rhetorical models, and revisions. Includes sections for abstracts, letters and business English.
English Online France Writing site
A nice site with a variety of levels, starting with how to construct paragraphs to ordering sentences and ordering paragraphs.
Paradigm Online Writing
Great website for advanced writers. It is really more of a site for native speakers, but is really well done, covering everything from brainstorming to thesis statements to support, revising and documenting.
ESL Flow Links list
ESL Flow is a website with a lot of links for different skills sets. This is for the writing page, which has some really good introductions to paragraphs and essays. There are outlines, exercisesfor paragraph and essay structure, example writing. Some of the links are old, but many of them are fantastic resources.
Guide to Writing a Basic Essay
Nice, concise multi-page introduction to the essay with a sample essay.
Narrative Paragraph Powerpoint
Different types of Introductory Paragraphs