How do foreign language teachers that teach a language that is not native to them (see details)?

.. speak the language so fluently and think in it like a native speaker? I would like to be able to speak a foreign language like that but it seems that after learning the numbers, months, seasons, and greetings it becomes extremely difficult to keep up with verb conjugation and memorizing all the vocabulary. However, I have tried Pimsleur and was pleased at how it gets you to "think in the target language" for a few minutes. I thought that was a big help. The drawback of Pimsleur is you don't learn very much in an 8-30 unit lesson. I've learned that to have functional fluency you should know at least 800 words or so. With Pimsleur you probably learn less than 100. Has anyone else who doesn't have a knack for language discovered a language-learning technique that's like Pimsleur but is more extensive?