Most English teachers already have skills and experience around teaching composition.  I've included a guide of activities from Bright Hub Education here.  It has some good ideas, but some of the links are broken.  Nonetheless, it's not a a bad place to start

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TEDEd has a series of talks on writing and composition

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30 Ideas on Teaching Writing to High School Students

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A Series of 12 lessons (from 2003 UBC Education student)

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From Maine, an Adult Education Course on the Process of Writing.  You may find some useful materials here

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