How to Create a Successful Language Lesson

As teachers, especially language teachers, we do hope that our lessons can be deeply appreciated by our students. But how can we create a successful lesson? What are the key factors involved in teaching which affect the result of our lesson? What should we do? During the four weeks of visiting schools and colleges and attending lectures given by the professors in UK, I do think I have gained a lot. The more I think of the life and ways of studying here, the more I feel I should write something on this topic.