There are many online resources which develop the skill of writing in plain English :
1. Plain language course on: http://www.faa.gov/about/initiatives/plain_language/basic_course/ which teaches basic tools to help create plain language;
2. Plain Train on http://www.plainlanguagenetwork.org/plaintrain/ with tips and techniques for improving communication skills with the use of plain language;
3. Free guides on http://www.plainenglish.co.uk/free-guides.html offering advice on design and layout, writing letters, cv’s and reports, glossary of alternative terms (or undesirables);
4. 39 rules for writing plain English by W. D. Lutz: http://www.plainlanguagenetwork.org/Resources/lutz.html;
5. A Plain English Handbook: http://www.sec.gov/pdf/handbook.pdf;
6. Free Plain English guides from Plain Language Commission on: http://www.clearest.co.uk/pages/publications/freeguides;
7. Plain English Bibliography: http://www.scotland.gov.uk/Publications/2006/02/17093804/5.
8. Publication on common errors in English: http://public.wsu.edu/~brians/errors/
9. Garble’s writing resources for plain English: http://home.comcast.net/~garbl/center/#.Ui8bhYzwHDc
10. List of 75 online legal writing resources: http://goingpaperlessblog.com/2010/04/14/75-online-legal-writing-resources-just-in-time-for-summer-associates/