It also depends on what you practice - if you keep learning vocabulary, for example, without much practice, you may not achieve excellent results. You should combine resources and methods. I suggest you try Capego or eslcourses for improving listening and spelling, and Saundz for pronunciation practice. If you combine these resources with practicing grammar from a grammar book such as Oxford, you should be able to improve your skills. If you stick to 1 hour a day long enough, I believe you'd become fluent.