http://www.copyblogger.com/copywriting-101/
http://www.awaionline.com/content/
http://www.brainpickings.org/index.php/2012/02/07/david-ogilvy-on-writing/
or just get this book to stand on the shoulders of the giants
http://books.google.co.in/books?id=PzkGAAAACAAJ&source=gbs_book_other_versions_r&cad=3
other tips:
read the newspaper cover to cover every day (good writers are informed)
learn anything about everything (good writers can connect the dots)
go for a walk (good writers let ideas gestate)
set aside at least fifteen minutes to write every day (good writers write)
من قبل
Purvi Kapadia , Supervisor Internal Communication - HR , Randstad - Deputed at Maersk Global
A few are here that have genuine guidelines...
http://www.slideshare.net/copywritingconsulting/copywriting-guidelines-for-beginners
http://en.wikipedia.org/wiki/Copywriting
Also if you have any friend in universities, then they would have access to their institutes presentations on the topic. Symbiosis offers such online guidelines that i know of...