I'm not a language teacher, but have a technical formation, I'm engineer.
The language I teach since 1996 is french, which I've learnt in the high-school, and practiced working in France for almost four years.
The other languages I've learnt alone. Russian and the ukrainian language, mainly through Internet.
Since 1996 I give personal classes of french and basic german.
And since 2006 I'm teaching on Internet, through Skype, with similar results.
The technical formation has helped me to concentrate the classes on the basic frames of the language, regarding it as a structure, composed of basic and accessorial elements. The concentration on the basic structures allows me to give a fundamental knowledge (of french language, for instance) in only 25 hours.