There is only one way to make students speak English fluently, what is it?

According to me the better way is to try to use always and only English during the lessons,  trying to avoid the use of the motherlanguage of the student. It's better if the teacher is an English mother language, and also should be really passionate on what is he/she doing.

By keep asking them questions or brainstorms to motivate them & encourage them to speak out loud & let them all participate in the discussion