As much as possible. Keep your eyes off the clock, and remember to do the writing/grammar/reading/listening side as well... that'll improve your speaking too!

3 months :)

Thanks for all you answers!^^

One or 2 hours per week, for 6 months to a year, is sufficient. What it really depends upon is how much work the student is willing to do outside of those meetings. For example, if I e-mail the student the lyrics to a song for study, and they read it once with me, and then never look at it again, they are not going to develop a "fluency".

About 2 years if you are under 10 years of age and going to an all English school. About 5 years if you are between 10 and 15. Otherwise if you are an adult and living in an English-speaking environment, it will be 10 years to 20 years . So be patient.