How to learn and speak fluent English

I have been tutoring English for more than one year. Determination is a key factor in learning English. It is not difficult to learn and speak fluent English depending on your attitude. It takes between 70 to 1000 hours to learn conversational English for the beginners. However, the time taken to learn English depends on the level that the learner wants to reach. My students have always shown great improvement since I took them through English. However there are some who take quite a long time to show improvement, I have tried looking at their weakness and handled them with extra care.