There are hundreds of books on teaching English, from grammar to business English. I think you need to decide what you want to focus on in your classes. You should take complete beginners through vocabulary and grammar in progressive stages: use a course book like the "Headway" series and see how they do it.
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NewguestI know that the best way to learn yourself how to teach is, probably, to participate in a, for example, CELTA course. However, it's pretty expensive, at least for me, for the time being.