This Webpage is a bit long but it has some interesting ways of looking at rhetoric and problem solving. I recoment you skim throught because there is some interesting findings.
Conceren with effect. This is an interesting definition because when writing with the purpose of causing audience to act upon something you are most conserned with the effect your writing will have. If your writing has had the effect you desire than you have created a good piece of writing.
Holy disclaimer in the "I agree" section! But an enterprising business nonetheless! And some of it is free...any takers? you would already have to be somewhat multi lingual to confirm their accuracy.
The website put forth by the Localization Industry Standards Association. A member based organization that provides consulting and guidelines for organizations to do business globally.
This is a good tool offered by the University of Toronto. The article "Supporting your Talk with Visuals," provides good tips for adequatly formatting visuals in powerpoints which is a form of technical communication.