Here you can find ideas for teaching English to different age groups in different contexts.
My golden teaching English tip is that if a learner doesn't understand or is unable to perform a task, it's not their fault. It's all about the teacher's instructions and the tasks they set. You can often help your learners by giving simple instructions, grading the task or changing it altogether.
For the time being, take a look at teachingenglish dot org dot uk. It's one of the best online resources for teachers of English.
I strongly recommend The Teachers' Room from BBC Learning English dot com.