I think the best way is balance of grammatic rules, exercises, communication with native and translation, watching TV and etc. A proportion of this parts is diferrent for each person...
But only one I know well: the learning language is regular brain work. There is no king's ways to do it.

Each man has his method which he think is the best way to master a language.

I think, the best way would be going to the place where people speak that language I'm trying to learn and be surrounded by native speakers there. :) When you're amongst the people that speak only this particular language, you don't have any choice rather than to start speaking yourself in that language. :)

But if it's impossible, I try to use different methods and search for native speakers that are willing to help me. However, I don't count on them only but I try to learn by myself also using books, internet sourses, courses, music, etc.

just find the persone who knows your language and that which u want to learn

get married on the native speaker

I have found the best way to learn another language is the way you learned your native tongue - by listening and repeating. You were fluent before you learned to read and write the language. In high school I learned French this way - no English was spoken. And even now, many years later, I still remember it. Several years ago when I was in university I studied Russian using the traditional method, by reading and writing, but soon forgot most of it because I had no one with whom I could speak it. Now I have been listening to Russian CD's which say a phrase and then which prompt me to repeat it and I am remembering so much more. The problem I have now is that I have completed the course and no more CD's are available. Fortunately, I have found some very good Russian speaking friends who will speak with me on Skype so I can continue to listen and repeat.

Great british poet lord Byron was polyglote, because he had had
a lot of girfriends of different nations. :)
Maybe it is legend. But I think it is kind of very stong stimul - to teach
language of your lover :))))

is to marry that language speaking person