I taught English to adult speakers of other languages in Germany and the United States between 1990 and 2010. Some was freelance, but most of it was in private language schools in Munich, Augsburg, and Washington, DC. In Germany, some of the classes were on-site company courses as well, including for buyers at a department store, mechanics at an airplane manufacturer, and bank tellers.
My students ran the gamut from nearly total beginners to fluent speakers trying to improve their range and accuracy. In each case, my main goal was to get the students to actively use English in ways relevant to their particular needs.
In Washington, I ran a blog called Language for You. A lot of the posts dealt with specific language-learning issues I was encountering among intermediate and upper-level students. For now, I have only made the following general posts available here.