Now we have a TKT book as a PDF file of suitable quality. It is “The TKT (Teaching Knowledge Test) Course, Modules 1, 2 and 3”
You can read about this exam here http://www.cambridgeenglish.org/teaching-english/teaching-qualifications/tkt/
It is a Cambridge exam. It actually checks whether you have some knowledge about how to teach English. If you are successful in passing this test you will get a diploma like that: http://ipolyglot.net/tkt2.jpg
If you are a private teacher, this document will make it easier for you to find students on any of many Internet sites where students can be found.
Now it is also possible to pass this exam via computer. It was not so two years ago.
Having learned this stuff you will know basic principles and words that related to teaching English. You will have an opportunity to review your own approaches.
Actually they (Cambridge folks) are not aware of best methods of studying English. We can discuss them ourselves.
So, next Sunday we can see whether we have enough participants interested in that exam. If there are enough people who are interested in that exam we can organize it. But it is a serious work. And there is some work you have to do on your own.